Expression Blend 3 Preview adds support for integration with Team Foundation Server, one of our top feature requests.
Some examples of the various integration points:
a) Saving a file automatically checks it out
b) Adding a new UserControl or assets to a project automatically adds them to source control
c) Renaming or deleting files automatically renames or deletes items under source control
d) Right clicking on an item that has been modified under source control allows you to submit that particular change
e) View history, get latest versions of files or specific versions, undo changes, etc.
To enable source control for a solution open inside Blend, the solution must be bound and residing in a valid workspace on the client. You can refer to the Visual Studio documentation on how to setup a solution under TFS source control here.
While you don't need to have Visual Studio 2008 installed on the machine to avail TFS support inside Blend, you do need to install Visual Studio Team System 2008 Team Explorer, a free download. You also need to install SP1 of Team Explorer, and a hotfix for Team Explorer SP1 that enables TFS support inside Blend - you can download that from here.