If i am on my MacBook Pro's iMessage and messaging someone that has an iPhone through iMessage will their replies and my messages show up on their phone bill. if it shows up will it be as data or as texting?
iMessage uses data not SMS. It can use either Wifi or 3G. However, it is a free service for all users. The only charge anyone can receive for iMessage is if they had to pay for every byte of data they used, but most contracts and even pay as you go offers data, and iMessage doesn't use up much data unless you send a photo or video.