"Wolfram Mathematica 8 for Linux/Windows/Mac"
Download This Torrent
||Software > Other operating systems
To get more info on what is new in this version visit - http://www.wolfram.com/mathematica/new-in-8/
To get a license working - when it asks you your activation key, you need to select:
"other ways to register" -> "Manual Activation" -> use keygen (select "style 23" if using "4.0.0 HardWisdom")
There isn't a specific license for Mathematica v8 in this release, but it have been reported by other users that previous licenses also appear to work. For example, a license generated by "4.0.0 HardWisdom" worked with v7 for me and was automatically accepted by v8 after I installed it and run it for the first time.