Tim Sneath from Microsoft has published 30 tips and tricks to try on the new Windows 7 which can be read here. What interest me is that Windows 7 can be installed via USB just by copying the content of the DVD to a USB. It is also said that the performance of Windows 7 is better then Vista AND XP.
After downloading check the integrity of the file using a hash calculator such as HashCalc.
32-bit version hashes:
MD5 - f9dce6ebd0a63930b44d8ae802b63825
SHA1 - 6071184282b2156ff61cdc5260545c078cca31ee
64-bit version hashes:
MD5 - 773fc9cc60338c612af716a2a14f177d
SHA1 - E09fdbc1cb3a92cf6cc872040fdaf65553ab62a5
CRC - 8E2FAD39
If you are in need to run multiple versions of firefox in you PC, such as having both 126.96.36.199 and 3.0b5 at the same time, then this is basically how you do it.
You can get the latest beta version from here, which is 3.0 beta 5 by the time of this writing