For those with access to MSDN Subscriber Downloads, when you go to download the DVD image for this release, you should grab the following while you're there to maximize your Team System CTP experience:

• SQL Server 2005 Developer Edition Beta 2 (English)
  You'll need this as a prereq for installing Team Foundation.
  
• Office Standard Enterprise Edition 2003 (English) or Office Professional Enterprise Edition 2003 (English)
  You'll need one of these to install Microsoft Word and Microsoft Excel; Microsoft Word for creating document-based manual test and Microsoft Excel as a prereq for using the Microsoft Excel integration features of the project management tools.
  
• Office Project Professional 2003 (English)
  You'll need this one as a prereq for using the Microsoft Project integration features of the project management tools.

Also, be sure to grab these downloads, too:

• Microsoft Solutions Framework Version 4.0, Beta
  Microsoft Solutions Framework (MSF) offers guidance in how to organize people and projects to plan, build, and deploy technology solutions successfully and effectively. The contents of the site represent pre-release versions of MSF v4.0.
  
• Visual Studio 2005 Team System Prerelease Documentation Update
  The Microsoft Visual Studio 2005 Beta 1 Refresh with Microsoft Visual Studio 2005 Team System release includes the same version of the MSDN Library that shipped with Microsoft Visual Studio 2005 Beta 1. Some pre-release documentation for Visual Studio 2005 Team System is available from this GotDotNet Workspace as a documentation update for download and evaluation.
  
• Visual Studio 2005 Team System Prerelease Walkthrough Projects
  These walkthrough projects will help you exercise the functionality of Visual Studio 2005 Team System. These walkthrough projects support the walkthroughs on unit testing, web testing, load testing, profiling and code analysis that appear in the Visual Studio 2005 Team System prerelease documentation.
  
• Visual Studio 2005 Team System Prerelease Utilities
  Utilities that support prerelase versions of Microsoft Visual Studio 2005 Team System. Some of these utilities may ship as-is in the final release, while others may be integrated as functionality in the retail release of Visual Studio 2005 Team System.

UPDATE The readme for Visual Studio 2005 Team System is available online:

http://lab.msdn.microsoft.com/vs2005/teamsystem/readme.aspx

We've moved the Team System site to http://labs.msdn.microsoft.com/vs2005/teamsystem to be closer to the rest of the Visual Studio 2005 family.

UPDATE Although this is called a Beta 1 Refresh, you cannot install it over top of Beta 1. And if you're not interested in using any of the Team System features, you won't likely see any difference between the two.

UPDATE for Virtual PC 2004 users...

For those that are trying to mount the DVD .iso image in Virtual PC 2004, you'll likely encounter the same problem Matt Berther is having - you can't. But Robert Moir has a tip on his site from Jeroen Pluimers that might work for you. See item 7.8 for more information:

VPC FAQ 7 - Known Issues with VPC 2004 - Robert Moir's Website

Virtual PC 2004 currently only supports disk sizes up to 2.2 Gb. One workaround which I've seen, but not tested myself, is to use virtual CD software to mount the ISO image as a virtual CD, then connect Virtual PC to the drive letter your virtual CD is using as if it were a normal CD/DVD drive.

Note While there was no official testing of this release on Virtual PC 2004, I don't know of any reason why it shouldn't work. It worked for me using images on Virtual Server 2005, but your mileage may vary.