TfsRedirect can be used to determine the TFS Web Access URL from within SharePoint. Although it's not exactly what you want, and it's a little hacky - you can pass the parameter tf:Test=1
to get the TFS team project that is associated with the site that your web part is being displayed on.
See John Socha-Leialoha's blog post on Using TfsRedirect to Display Reports in TFS 2010 Dashboards
What is TfsRedirect?
Here’s the scenario. You had TFS create a dashboard site in SharePoint
when you created your team project (or you added it later as described
here). There are several items on this dashboard that point to other
locations that are potentially on other servers:
- Team Web Access
- Process Guidance
- Reports shown on the dashboard pages
TFS itself know where to find these assets. And the locations can
change if, for example, the TFS administrator moves the reports to a
different server.
Rather than hard-code the locations of these assets into the
dashboard, the TFS team created a web page called TfsRedirect.aspx
that knows where these different assets are located, and will redirect
to that page.