Anytune Pro+ (slow downer,pitch shift, etc) App for Ipad is cheap right now. Don't know how long for.

I use it all the time - LOVE it to death. So nice that the tune doesn't advance at the end or start as soon as it's cued up. It remembers tempo and transposition changes for each song, and pops up text if attached to the file.
Hint:
Use it in landscape mode and the playlist stays visible so you can select the next song. At least, that's the way it works on my iPad mini - maybe the full size iPad is different.

Highly recommended.