An I-Phone question -- I've paid for the I-Pad app and when it came on my I-Pad there was a notice that I could be charge data rates. I don't have 3G on my I-Pad and just wifi, so there can't be any extra charges, right? Wouldn't that only be if I used it on an I-Phone (not I-Pad) that had a limited account? Anyone know for sure? Thanks.