What do I need to go from 12V, 10 amp to 12V, 2 amp ?

#1... I know little or nothing about electronics, amps, ohms, diodes, etc.

That being said

I got a little motorcycle MP3 amp to put in the console in my jalopy, I plan on running my little $39 2GB Sansa (has FM radio too) through it to some hidden kick panel speakers, so I don't have a modern radio ugly-ing up my dash.

The amp has a plug for an A/C adapter in it, it wants 12V, 2 amps.... how do I make sure that it does't go "pop" when the fuse in the fusebox for the radio circuit I plan on using is 20 amp?

 

Put a 2 amp fuse inline. Although the device will only accept what it needs, the fuse will protect it.

 

Just go to radio shack and get a 'in line' fuse holder and put a 5amp fuse it and you should be fine. Just put it in series with your power to your MP3 stuff. Also don't short anything out and you'll be good too...