Another good news is multiple language downloads now available: Next build (10049, build 10056, build 10098, build 10061…) coming soon.

If you have not been able to update to build 10041 or you are installing the Windows 10 Technical Preview for the first time here is how you can skip the earlier builds and start with the most recent build as of March 18th, 2015.
Create a bootable USB for Windows 10 installation
Create a bootable USB for Windows 10 installation

Hopefully the next build, which is due to be released soon (100XX) will have .ISO files available .
For your information, you can download Windows 10 Build 10056 ISO file here. If you have problem regarding to installing Windows 10 Build 10041 and 10049, please read this:
https://www.windows10insider.com/2015/04/problems-install-windows10-build-10041-and-10049.html

If you have any other issue relating to this, please leave a feedback in the comment section below.

Details

1) Download the appropriate .ISO file using the links listed below.
Product key: NKJFK-GPHP7-G8C3J-P6JXR-HQRJR
 (Not required, for mitigation purposes only)
English (United States)                                          Download Links                                     SHA1 Hash Value
Windows 10 Technical Preview (x64) – Build 10041  Download (3.4 GB)   C535BC08C862467A19DBBC3A320D7E718834255B
Windows 10 Technical Preview (x86) – Build 10041  Download (2.53 GB)   2A9213F2774C5D323A6231EAB25CC23F99B4B6FC
English (United Kingdom)
Windows 10 Technical Preview (x64) – Build 10041  Download (3.46 GB)   2FA6109546DE5730E3D54DDE22B24051F686F564
Windows 10 Technical Preview (x86) – Build 10041  Download (2.57 GB)   0742C9025B7A2FF6994D5EEA9FEBC2BF1AC0C159
Chinese (Simplified)
Windows 10 Technical Preview (x64) – Build 10041  Download (3.63 GB)   75BBDE99FCCC521584B32A3B80BD628AE20A965A
Windows 10 Technical Preview (x86) – Build 10041  Download (2.73 GB)   B9C25B4C9F0EF1C5082D8646363E42CE136C3E12
Portuguese (Brazilian)
Windows 10 Technical Preview (x64) – Build 10041  Download (3.38 GB)   E668DDA4885EDDA4CE17951B55B905036777246B
Windows 10 Technical Preview (x86) – Build 10041  Download (2.5 GB)   0EDADA3852CCC144345A4F38F81298157B8589BA
German
Windows 10 Technical Preview (x64) – Build 10041  Download (3.47 GB)   357272FFF5897AB5D4BD4E6C10BE1DA9ACEC4ACC
Windows 10 Technical Preview (x86) – Build 10041  Download (2.58 GB)   82270A23C8D8084247D63D29336BCDDB25F42C54
French
Windows 10 Technical Preview (x64) – Build 10041  Download (3.44 GB)   78E85A4FCA2BDECB6DD0C1C99371E65FEC60A4C4
Windows 10 Technical Preview (x86) – Build 10041  Download (2.56 GB)   995B92C34A07B4DE85B9768FF197B58CAA9A491C
French (Canada)
Windows 10 Technical Preview (x64) – Build 10041  Download (3.35 GB)   0F994878BB1DE533DE4AA2ABE3DBF5FC48EF1B54
Windows 10 Technical Preview (x86) – Build 10041  Download (2.46 GB)   9ED8C2DCF12C50C6947DBCCD81ABDB5C13C76288
Russian
Windows 10 Technical Preview (x64) – Build 10041  Download (3.41 GB)   C0B4B807AE007710DC0EDEA6FF2B862DF7FAE3F3
Windows 10 Technical Preview (x86) – Build 10041  Download (2.51 GB)   983289940252061EA5AD75A5522C8C8DECB27A11
Japanese
Windows 10 Technical Preview (x64) – Build 10041  Download (3.52 GB)   44E1A02CD5C1E8F8332469A248C8DB97D4D5DF33
Windows 10 Technical Preview (x86) – Build 10041  Download (2.62 GB)   7B706A05BFACA12EABFBB0FB69E96B22EAEECFE9
Italian
Windows 10 Technical Preview (x64) – Build 10041  Download (3.38 GB)   82A8E9C8D9A665AF258717353513D704B37D278A
Windows 10 Technical Preview (x86) – Build 10041  Download (2.52 GB)   2AEA4C9A6AFFE61EAC9F5A4D68BF6B799D236C9C
Dutch
Windows 10 Technical Preview (x64) – Build 10041  Download (3.34 GB)   106FCE8D9B1A86CEA7A8C1D36175C22BA4D47E19
Windows 10 Technical Preview (x86) – Build 10041  Download (2.48 GB)   5AFB8E3476929644D4BC63861300B4D5179FBFB8
Spanish
Windows 10 Technical Preview (x64) – Build 10041  Download (3.43 GB)   29F01F292DE69DC9072E3532CD56A2B22CFEA709
Windows 10 Technical Preview (x86) – Build 10041  Download (2.55 GB)   3E8BB89A776790DA5D2C8D1E3DD4430488514A37
Spanish (Latin America)
Windows 10 Technical Preview (x64) – Build 10041  Download (3.38 GB)   D23B989E63B23409BE15072F7D6E11B4497401BC
Windows 10 Technical Preview (x86) – Build 10041  Download (2.48 GB)   3A7469FA30D12F6161944A1C1DC82FC87439ACD4
Polish
Windows 10 Technical Preview (x64) – Build 10041  Download (3.38 GB)   65EC25B13D1D83E64B87D50FC55AF559E25BDAB5
Windows 10 Technical Preview (x86) – Build 10041  Download (2.49 GB)   2447DD7F65456C68D64B20A063ABBE48F2ACB43B
Turkish
Windows 10 Technical Preview (x64) – Build 10041  Download (3.36 GB)   68B1DEE0B16C080735D9E068FCF23E83FF2657E5
Windows 10 Technical Preview (x86) – Build 10041  Download (2.48 GB)   6823AF3046D4222BF0EA7570488356C1873A35D2
Swedish
Windows 10 Technical Preview (x64) – Build 10041  Download (3.35 GB)   A8BD81178C70A835F8A7718A8846D0CA36C93716
Windows 10 Technical Preview (x86) – Build 10041  Download (2.48 GB)   73314F5888E1483A6EDE2219A868848F975E85C3
Czech
Windows 10 Technical Preview (x64) – Build 10041  Download (3.37 GB)   533E245D6BCFEC3025EEDA2BB5060B6C2364A0E9
Windows 10 Technical Preview (x86) – Build 10041  Download (2.47 GB)   2EAC7C153368485B49C87F8E499ABEBBEBEF7E75
Arabic
Windows 10 Technical Preview (x64) – Build 10041  Download (3.37 GB)   D64B6A34C09093213EB3262AF7E445633D1D321A
Windows 10 Technical Preview (x86) – Build 10041  Download (2.52 GB)   8002F81C770CF972D413EB794A5FF1AF40E8C7B3
Korean
Windows 10 Technical Preview (x64) – Build 10041  Download (3.43 GB)   EE80BBE9F781E94B5CF828FEF10473741CD760CD
Windows 10 Technical Preview (x86) – Build 10041  Download (2.54 GB)   F09086D8AC0157AC397C828D3EBA3329F85A2041
Finnish
Windows 10 Technical Preview (x64) – Build 10041  Download (3.36 GB)   30CE7316C088177BFC4905903A87D64E1BDDFCB5
Windows 10 Technical Preview (x86) – Build 10041  Download (2.47 GB)   2239C599CA197457DE2D1C9463A425D667294DED
Thai
Windows 10 Technical Preview (x64) – Build 10041  Download (3.36 GB)   F81044896D5B2F41144E5947A4A469A4F004C166
Windows 10 Technical Preview (x86) – Build 10041  Download (2.47 GB)   D10B06CDC351F3849996EB61535CF12AA35F424C
2) After downloading the correct .iso file install HashCalc and validate the SHA1 hash value is correct.
HashCalc: http://www.slavasoft.com/hashcalc/index.htm
(Note: If the download is not corrupt, the value HashCalc returns will match the SHA1 value.)
a) Launch HashCalc and navigate to the location of the .iso file you downloaded.
(The default download location is: C:UsersUser account nameDownloads)
b) Remove all check marks from the list of HashCalc options except for SHA1.
c) Click the ‘Calculate’ button and wait for the SHA1 string of letters and number to be displayed.
Note: The hash value is not case sensitive as upper and lower case letters are considered the same.
3) Next use ImgBurn (or Gear ISO) to create a bootable DVD.
ImgBurn: http://www.majorgeeks.com/files/details/imgburn.html
Note: When installing ImgBurn, choose the “Custom Installation (advanced)” option and remove the check mark(s) to eliminate unwanted options, including Optimizer Pro (I do not accept) which is not needed.
Burning ISO Images with ImgBurn article: http://neosmart.net/wiki/display/G/Burning+ISO+Images+with+ImgBurn
(The steps are the same for Windows 7, Windows 8 or 10), except you are not creating a Repair disc but a full installation DVD)
Note: Always use high quality DVD+R media and the slowest burn speed (4x or 6x) if offered a choice.
Note: Skip to step #4 to create a bootable Flash / Thumb drive.
4) For instructions on creating a bootable USB Flash drive to install Windows 7, 8 or 10:
Read: http://www.sevenforums.com/tutorials/2432-usb-windows-7-installation-key-drive-create.html
Or: http://arstechnica.com/business/2009/12/the-usb-flash-drive/
Optional software to create a Bootable Windows 7 DVD