i'm looking for an app for our small office that would be used as help desk for submitting tickets/computer related issues etc. Nothing to complex. Since we're also using TFS for bug tracking i would like to integrate it with TFS.
You could try Kayako - http://www.kayako.com
They are writing a REST Api that you should be able to integrate TFS with
http://forums.kayako.com/threads/microsoft-tfs-2010-integration.23893/