Last night Microsoft launched the final release of the .NET Framework 3.0 (formerly WinFX). I ran the quick installer on two machines today, and the setup worked perfectly both times. Not even a restart required. If you’d like to check out the release notes before installing, they are available here.
Download the quick installer
Download the full x86 redistributable
Download the full x64 redistributable
This is a very important release for developers using Microsoft technologies, because it makes some key Windows Vista components available for Windows XP and Windows Server 2003. Of course the developer tools aren’t quite ready for primetime, but they’ll get there.
Read: NetFX3
MasterMaq's Blog 
Any idea when programs are going to start requiring this? I’d install it, but I really don’t see the point right now.
Starting with Office 2007 I guess 🙂
Actually, you probably already have the .NET Framework 2.0, so you’re good to go. I wouldn’t expect the other technologies (WPF, WCF, WF, etc) to become that popular until Vista ships.
The developer tools for Windows Workflow Foundation are ready to go. They are released and fully supported. There is also a CTP for the tools around WCF and WPF, if you have any feedback on those, please let us know.
Thanks Matt, I didn’t realize the WF tools were ready, I thought they were in CTP like the rest. Cool!