Can I go on AIM with ONLY an unlimited data plan with AT&T on a HTC Fuze phone?

How do I do this?

Will each IM count as an individual text message or is it totally separate and will only count towards my unlimited data plan?


I'm trying to get down all the facts because I'm getting the phone next week and my parents are willing to pay for only an unlimited data plan. So if I can go on AIM with just the unlimited data plan, I'd rather just go with that because I don't want to fork over an extra $20 a month for an unlimited texting plan. Thank you.