Adding proper category support is in line with Maemo's goal of better Mainstream Linux Alignment.

For the list of proper categories (Appendix A of the Menu Spec) and the format of .desktop files, see Desktop Entry Spec and the Desktop Menu Spec. It's better to use this proven (and widely-supported) category system than to invent a new one, and applications ported from the Linux Desktop most likely already have a proper category entry.

Oh, and as some other people have already pointed out, please gettextize your program and publish the source and ideally link the source repo to Transifex, so community members from all over the world can start submitting translations for your application Publishing the source is really more helpful than you might think.