It's been talked about before... I wish it really worked like a real machinedrum... that would make it a must have. Unfortunately... it is more like a Boss DR-220.
For a little history of PSP Rhythm, each version was designed after our favorite drum machines. The latest versions were modeled after the machinedrum/monomachine because those have the best modern user intefaces (I have and love both).
The very latest version 5 has a realtime synth onboard (modeled after the TB-303) and an effects section of LPF/HPF, slicer, delay, distortion.
The editable sample parameters are:
Pitch (semitones) Volume Balance Start time End time Flam Reverse Cutoff Resonance
Version 6 will be out within a couple of weeks and has a lot more features.
I just wanted everyone to know that it is quite different than a boss DR-220 (at least looks a lot nicer!). The best thing is that you can put in your own samples, up to about 18 megs combined in 15 samples (limit of PSP usuable memory). Plus, it's free!