1. ok.. i use grip to rip cd's personally. as for organization, i don't know... i guess it's down to how you play them back really. i'm just a fan of decent directory trees.
2. easy enough.
3. never heard of them... i expect it's pretty simple.
4. yeah easy. don't use telnet though, use ssh for a text connection, or you might prefer vnc or somethign for a gui connection
if it's really only mp3.. well nothing more than a 400mhz celeron / duron would be strictly needed... won't be super fast, but it's only audio, and tehre are some apps that would give not tooooo awful video playback on a machine of that spec.