Try this:
Open a Visual Studio Command Prompt (All Programs | Visual studio | Visual Studio Tools | Developer Command Prompt
(this is just a normal command prompt but with some extra env variables set, and with the visual studio tools in your path).
use the cd command to switch directory to the root directory that your project is in on your local disk that you want to compare: example: cd \MyProjects\TheProject
execute this command:
tf folderdiff . $/The/Tfs/Folder/Path/To/Corresponding/ProjectDir/On/Server /recursive /view:different
(there is a space between the "folderdiff" and the ".", and another space between the "." and the $/ The "." just says "use the current local path (you should be sitting on it). Being on the current path also gives the TFS command the context that it needs so that it knows how to connect to your TFS server, and which team project and collection to use.