I have some cutting edge (and bleeding edge) customers.  They don't necessarily enjoy playing the unsynchronized-product-release-cycle dance.  When we release a product, we make it work with what is shipping at the time.  So, for example,when TFS shipped, WSS 2.0 was the standard.  Now that WSS 3.0 has been released, you'll need to wait until the next release of TFS in order to have out-of-the-box integration.  (In theory, at least.  I'm not in a position to promise upcoming product features.)

If you want to live on the edge, however, we've published guidance on how to integrate TFS 2005 with WSS 3.0.  If you want to give it a try, hop on over to Brian's blog. 

Link to Brian Keller: Technical Evangelist for Team System : Configuring Visual Studio 2005 Team Foundation Server with Windows SharePoint Services 3.0