My Ipod's battery has started to die, and currently it only runs for ~1 hour after being fully charged.

These are my questions

1) is it possible to get the battery in my existing ipod replaced? If so, how?
2) What are the substitutes for an ipod, what are they like and how much do they cost?
3) Can i load the songs from ITunes onto other mp3 players?

Thankyou anyone who replies