Brian Harry talks about the documentation on how to move your TFS SharePoint installation to a different server. It's important to note that he calls this out as not being a trivial undertaking, so you'll want to be extremely cautious.
We've gotten tons of requests since we shipped TFS v1.0 from customers who want more flexibility with the configuration of the SharePoint server that TFS uses. Some want to use a SharePoint web farm that they already have. Others want to use a pre-existing web site. And still others want to change the port # or not have a SharePoint site at all.