If your program is free software, there is a whole GNOME subproject devoted to helping you make translations, the GNOME Translation Project.

The way it works is that you contact the gnome-i18n mailing list to find out how the translators can access your po/ subdirectory, and to add your project to the big status tables.

Then you make sure you update the file POTFILES.in in the po/ subdirectory (intltool-update -M can help with this) so that the translators always access updated myprogram.pot files, and simply freeze the strings at least a couple of days before you make a new release, announcing it on gnome-i18n. Depending on the number of strings your program contains and how popular it is, the translations will then start to tick in as languagename.po files.

Note that most language teams only consist of 1-3 persons, so if your program contains a lot of strings, it might last a while before anyone has the time to look at it. Also, most translators do not want to waste their time (translating is a very time-consuming task) so if they do not assess your project as being really serious (in the sense that it is polished and being maintained) they may decide to spend their time on some other project.