Brian Harry blogged about Installing TFS 2008 on Windows 2008, and referenced Etienne Tremblay's guide to installing TFS 2008 on Windows 2008.

I used Etienne's guide to do it myself. I installed it on a VPC. There are a couple of things  that that I had to learn. 

First, if you're like me, you installed Visual Studio before Team Foundation Server. That installed SQL Server Express. Unfortunately, the SQL Server Express install will block the installation of the SQL Server 2005 BIDS and Management Studio because the "Tools" folder already exists. I had to go to "<install drive>:\Program Files\Microsoft SQL Server\90\" and rename the "Tools" folder to "Express Tools". Then I installed SQL 2005, and got a full suite of the tools.

Second, if you have the installation guide, you need to know where to look for the SharePoint setup instructions.

1. First, get the latest version of the "TFSInstallGuide" at http://go.microsoft.com/fwlink/?LinkId=79226.
2. Second, go and find the instructions for installing SharePoint at "/Installing Team Foundation Server/Prerequisites for Team Foundation Server/How to: Install SharePoint Products and Technologies on Windows Server".
• If that's too much searching, click on the search tab and enter the text "stsadm", then click "List Topics"; you'll only see one result.
3. Be careful when you get to step #19.
1. You'll have to open a command prompt AS ADMINISTRATOR to type in the commands. That is, you have to right-click and choose "run as administrator" rather than just opening the command prompt. I widened my command shell to 150 characters so I could see the entire command. I also set
   >SET PROMPT=[$P]$_:$G
   so that I would have a nearly empty line to type on. Of course, my prompt is two lines now, but it's OK with me.
2. Then you have to type in this line:
   stsadm.exe -o extendvs -exclusivelyusentlm -url http://WSSServerName:80 -ownerlogin Domain\UserName -owneremail "admin@localhost" -sitetemplate sts -description "Description"
   The italicized bits are the parts you replace with your local versions. I found that "Description" (called out in red above) had to be "Default Web Site", or I got two web sites on port 80.

The final thing I learned (again)--don't put your virtual hard drive (*.vhd) files in a compressed folder. I did that by accident, and it robbed me of performance.