As you probably already know, all gPodder versions (Linux Desktop, Maemo 4 and Maemo 5) use the same codebase, and as Python is an interpreted language, the choice of which UI to run can be made at run time (you could do this for compiled languages, too, but it's easier for interpreted ones). In current versions of gPodder, this happens by using command-line arguments.
gpodder alone will start the Desktop version (which does not work on Maemo for obvious reasons - an "auto-detect" feature might be implemented in the future). On Maemo 5, you will usually want to use
gpodder --fremantle, which will start the Maemo 5 UI as you know it (that's also the command that gets executed when gPodder is started from its application icon). On Maemo 4, the command is
If you are a gPodder/Maemo old-timer, you might still remember the "good old days" of two-panel, stylus-based podcast goodness with multiple selections, the funky context menu and the thick toolbar on your N8x0. Ever wondered how that would feel on the N900? Try it out! Simply run
gpodder --maemo in X Terminal and give your podcasts a little retro interaction (the database and downloads are the same in both versions and are therefore shared).
Try it out - it might come in handy if you are a stylus cowboy or have really small fingers (or a big N900 and normal-sized fingers...). Also, give the multiple-selection feature in the episode list a try. All you need is gPodder version 2.5, as it contains some compatibility fixes to make the Diablo version not be totally unusable on Fremantle.