Turning your Axim into a music player is as easy as 1-2-Freeware! Some people prefer the simple and low-memory using GSPlayer; as for me, Mortplayer is my free player of choice. And lucky for everyone, they've just released a new version:
Mortplayer 3.3
For those who haven't yet tried this player, I certainly suggest it. It's one of those feature-rich players that has plenty to offer. A favorite feature seems to be the "Car Screen" mode, made for big-thumbed control :)