Just would like to say:
Milkytracker on the PDA is hands down the best portable music software out there at the moment and has been for years..
Use milkytracker to compose, then export xm files into a more modern tracker, add DSP effects, VST synths etc....beautiful!
the competition is
LSDJ: [Gameboy, PSP] cool gameboy specific sound, very limited sampling options, innacurate BPM, incompatable with other trackers so no export to renoise/something else with DSP effects
Nanoloop: [Gameboy, gameboy advance] this is a really really cool program..step sequencer, not tracker. rendering for sampling possible but troublesome.
LGPT: [PSP, GP2X] excellent program, clone of LSDJ but with more tracks, wicked effect commands such as loop offset and filter....very cool program for PSP, but incompatible for exporting songs (you can always sample by rendering output tho!- and in real time with live mode and track mutes, individual track render, solo channel etc!!!!)
GRIFF: [PDA] really nice sound, stupid piano roll -> lame, expensive, lame
SYNTRAX: [PDA] really great synth sounds, can sound awesome...piano roll = lame
By the way, keyboard is not necessary for using milkytracker!! use the stylus and the directional pad on the PDA for navigation. other buttons can be assigned to whatever (loop current pattern, stop, play song etc.) This is really nice way to track, very comfortable once you get used to it...whats all the fuss about HP jornada 720?, they are lame, only 51mhz...get something better for same price!! dont need keyboard!!!!
alright thats the end of my rant...phew