During testing ClickOnce-Deployment i wondered that in my start-menu an "application reference" is created which has no link-reference to the application which is installed at the client.
Only references to the server which offers the applicaton are listed.
It seems there is some magic in the ClickOnce-client-engine of .NET-FW 2.0
After searching in my user-profile i found the application under ..\Local Settings\Apps\2.0\.. in a randomly named folder.
BTW: uninstalling is done by:
rundll32.exe dfshim.dll,ShArpMaintain <ApplicationName>.application, Culture=neutral, PublicKeyToken=..., processorArchitecture=msil
this pops up an uninstall dialog ....