Any software for Mac that can change pitch of my MP3's?

Well, I'd like to sing some of my songs that I have on my computer and whatnot, but I have a slightly unique vocal range. So I would need to change the pitch of many songs to comfortably sing with them. I was wondering if there is any sort of free software that I would be able to manipulate the pitch of and play songs in.

Thanks.

Audacity has a pitch changer. Check it out here. Its also a semi-powerful audio editor.

Dylan

Alright, thanks.
I used to use Audacity for other things, but the pitch changer was really screwed up back then. It works decent now though, I guess. I can use it.
Thanks again.