Thats probably nor very precise but just to begin:
The ps2 has like a pc some components. For example the gs-graphics-chip. There are also other components like EE, VU(1/2), GIF, FIFO and some more but these are those which I remember. All have to be emulated since there are no corresponding chips in your pc.
SuperVU is just an old version of the VU-emulator and microVu is the currently enhanced version. Nevertheless SuperVU seems to provide higher compatibility or speed in some games wherefore it is still included. I actually never used it.
The way how an chip is emulated can be different. The two ways provided by pcsx2 are interpreter and recompiler. Interpreter is normally quite slow. Thats why we use recompiler all the time. I think there was also a third method proposed by some forum member but it seems not to be interesting enough.
Clamping modes is the way how to handle exceptional numbers if I am correct.
So in normal pc's there are some exceptional numbers like NaN (not a number) and INF (infinity) and you can calculate with them like INF + 2 = INF, NaN+2 = NaN... but int he ps2 these numbers are not included. So that INF is replaced by the highest available number and that can lead to bugs... The way how to handle those numbers is just the clamping mode.
Edit:
Actually I have all my information from the
developers blog.
There is some quite interesting stuff written. Unfortunately there was nothing posted for some time.