When you open a project or solution from source control, Visual Studio downloads the latest version of the item and all contained files to your local working folder. After you retrieve a local copy of the item, you do not need to open it from source control again. You can proceed to use the source control commands from within Vault.
1. In Visual Studio, on the File menu, click Open.
2. Click Web Site.
3. In the Open Web Site dialog box, click Source Control to the left, then click Select Source Control Project.
4. Your SourceOffSite "Connect To Server" dialog will appear, you will then be prompted to log into SourceOffSite, choose your repository and then select your web project folder from the tree.
5. If you already have a local copy of the Web project you are opening from source control, you are prompted to overwrite the local copy of all files and projects in the solution. Respond to prompts as needed.
How to open a Web Project from Source Control in VS 2005
Moderator: SourceGear