Thanks to Paul Fauth for informing me that the Beta 2 Versions of Windows XP are now up on the MSDN site.

Windows® XP Home Edition Beta 2 (English)
Windows® XP Professional Beta 2 (English)
Windows® "Codename" Whistler Server Beta 2 (English)
Windows® "Codename" Whistler Advanced Server Beta 2 (English)
Windows® "Codename" Whistler Professional Edition Checked/Debug Build Beta 2 (English)
Windows® "Codename" Whistler Customer Support Diagnostics Beta 2 (English)
Platform SDK
Windows® Driver Development Kit

In order to successfully install and use Whistler Beta 2, you must:

1. Obtain a Product Key. This key is valid for 10 product activations, so be sure to keep it safe. If you lose your key, you can click this link again and the same key will be displayed. If you require additional product keys, please contact MSDN Customer Service.

2. After installation you will be asked to activate the installation, which requires a connection to the Internet. If you do not activate the installation Whistler Beta 2 will continue to function for 14 days. After 14 days you must activate.