You can't export a playlist from an iPod directly as far as I'm aware, you need to export it from iTunes.
In iTunes
File->Library->Export Playlist
Then change the "Save As" type to M3U
Considering you are posting this on the Musicbee forum, I assume you are using Musicbee in some capacity?
How are you adding tracks to the iPod? If you are using the iPod & iPhone driver plugin in Musicbee, that uses iTunes as an intermediary to add the tracks to the iPod, you should be able to just open iTunes by itself and export a playlist.