Recently I installed Team Foundation Server 2008 Beta 2 to use it as my main source control system.
One of the new features that I found out and started using regularly is the Offline mode.
Basically, when Team Explorer detects that there is no connection to the team foundation server, it switches to offline mode.
Once you connect back to TFS, you can click the Go Online button on the team explorer, it will scan all your files, compare them with the latest version on the source control, and shows you a list of changes that were made offline, and gives you the option to check the changes into source control.
A very welcomed addition, something that was missing in TFS 2005.