aim does that count as text for example if i text someones screen name that is on aim at home, from my phone using texting does it cost money or go into my unlimited plan?

NO! AIM is online it will charge because u need to be online in order to AIM people! texting is different! It will charge unless you have an unlimited internet access or special plan for the AIM. but if you dont it will charge!

It is a hybrid between texting and actual data use. This is because you have to sign in which cause data to be sent and not text. Also selecting an AIM user to send a message to also charges you for data. The only possible point you can be charged for texting is if you allow people to contact you and set up an option to send that to your text.
In the end you will be charged for data regardless of how you do it, but by not initiating the conversations, you save some money as long as you only send texts. Doing it this way is inconvienient, so i recommend getting a unlimited data plan.