Fancy that! i just purchased one of those a month and a half ago. Basically, what you heve is the T-mobile MDA. It runs Windows mobile 5 (depending on how new it is) and so it is a PPC device.
It is made by the Taiwanese company HTC which refers to it as the Wizard. It is also marketed under various names by different carriers, eg: Qtek 9100 / I-mate K-JAM / MDA Vario / O2 XDA Mini S / SPV M3000 / Cingular 8125 / T-Mobile MDA / Dopod 838 / VPA compact II.
So far, my experience with it has been excellent, given that i have modified the ROM at least 3 times in the last month or so. Loads of software available. Since i dont live in the USA, i had to remove the simlock from it to use over here.

But, i think u should get in touch with hiroprotagonist for more info. He is the one who give me pointers on what to mess around with. Since my MDA hasnt died on me yet, his advice has been pretty sound.
Holla if u need any help