Visual Studio 2008 Beta 2, along with Microsoft .NET 3.5 Beta 2, is available for download. Here's Soma's official announcement.
I find that downloading such huge sets of files requires a bit of help. My recommendation: Free Download Manager. This tool is awesome - indispensable in fact - if you do any downloads beyond small text files :) It does queued downloads, resumed downloads and throttling. Perhaps best of all, it does multi-threaded downloads, so it maximizes the use of your bandwidth when running at full throttle.
Update: Apparently there are some things you must do/fix before using VS 2008!! Read ScottGu's blog post about it!
Update 2: According to Juval Lowy, the svcutil.exe program in Beta 2 is broken.
A workaround is to copy an older (Beta 1?) version of svcutil.exe over the top of the Beta 2 version. Instead, Justin Smith says that you need to run "sn.exe -Vr svcutil.exe" - apparently then you don't need to copy an older verison over the new one.