I’ve been looking for a way to add non-package managed apps to the Gnome/KDE menus.
Recently, I installed Firefox 2, Eclipse and Jude this way but have found links telling me how to remove items from the application menu, no way to add them in.
Apparently some love between KDE and Gnome was reached in order to standardise the application menu and so it now resides in one place with all these .desktop files (aka shortcuts) to launch the desktop apps.
See Edit the Global KDE Menu Items from a console for SUSE Linux
[Edit]: Found some extra sites
The specification
SUSE realises they left something out