Sharp Zaurus

Does anyone here own a Sharp Zaurus? If so, i know these things *look* cool but what can you do with it? I'm looking to buy one of these, but I don't know much about them. I have a few questions, hopefully they can be answered. Will they run most Linux software, or does it need to be ported? If the software needs to be ported, is there a good availability of software? Other then the built-in keyboard and color screen, what advantages does this have over a PalmOS handheld? How do you expand it? Does it have PCMCIA, serial, Ethernet, etc... port? I can mp3 on it, right? And where can I buy one of these offline? thanx.