See this reference for information on how to bind/unbind your solution or project from source control. NOTE: this doesn't apply if you are using GIT and may not apply to versions later than VS2008.
Quoting from the reference:
To disconnect a solution or project from source control
In Visual Studio, open Solution Explorer and select the item(s) to disconnect.
On the File menu, click Source Control, then Change Source Control.
In the Change Source Control dialog box, click Disconnect.