You can use the /deleted switch with tf dir to list deleted items along with existent items. To undelete an item, you need to know its deletion ID, which will be a number preceded by X, for example: tf undelete $/proj/foo/bar.cs;X1234

To show deleted items in Source Control Explorer, you need to make sure you've selected this option:

Then you'll see the deleted items in Source Control Explorer, then you can just right click and choose undelete.

For more info on how to configure Visual Studio with Team Foundation Version Control, please read: http://msdn.microsoft.com/en-us/library/ms253064.aspx