The UA-100 is a very basic analog/midi interface that connects to the PC via USB. You have to be running Win98 to use it.
I haven't used it for MIDI, but did use it to record some samples for a pitch correction project. I didn't require extremely high quality stuff and found it ideal for a quick and easy method to record voice. The results were nice and clean but there was some definite colouration of the sound.
The unit also has 4 effects you can add to the input and the one of the analog inputs accepts line or mic levels. The second input is just for mic levels (both inputs are 1/4")
Personally I wouldn't use this thing in a mid/high quality PC based multitrack environment, but for basic demo quality recording it's great. It's very easy to use and very portable.
Cheers
Stephen