TFS was giving me the "Working..." message but nothing was working. I was trying to check in to source control, and the progress bar never completed. Turns out it was a plumbing problem, the intranet proxy server was timing out in its attempt to proxy HTTP requests for the web service calls and was clogging things up for me.
If this happens to you, try the following:
- IE -> Tools -> Internet Options -> Connections -> Lan Settings
- Make sure "Bypass proxy server for local addresses" is checked