Yeah, I don't want to risk that. And when I was researching about ipods I found some site that talked about how originally you couldn't get a replacement battery for them, that you just had to buy a new one. But I think everyone complained enough and now they'll replace the battery for you but it might cost a lot. Though, I'm not entirely sure if thats accurate or not as my ipod battery hasn't died yet~
I think that the batteries can be changed, but you have to get it done by one of those 'certified Apple resellers' or someone like that, and I imagine it would be expensive. Probably in excess of $50.