Though it is available as part of Windows XP service Pack 2 Reail CD, you can download the Microsoft Framework 1.1 Service Pack 1 separately if you are so inclined.
Thanks again Scott.
Ian Griffiths points out that Microsoft is planning on releasing their new gui code-named Avalon along with the rest of WinFX to Windows XP and Windows 2003 users.
I find it an odd strategy by Microsoft since those are the core elements of what makes Longhorn interesting to me as a user and a developer. But the faster these new technologies spread the sooner I can use and develop for them.