Modern Technology!

I think I'm the only person that I know who doesn't fully understand ipods! I've never really gotten it! Where do the songs come from? Do you have to pay for each and every one of them? If I have old CD's that I love, can I get songs from them too? See...you thought I was kidding! I know it's the hip, happenin' thing right now--but until talk radio shows up on an ipod...I have very little use for one! My husband on the other hand, would LOVE one!