quick questiong about texting and the lg enV

If theres an answer to this question else where, would someone kindly point me to that thread, thank you...I did a search and i wasnt able to come up with much but a little something here and there

On to my question...My dad has a family share plan, so he decided to add a line for me for $9.99 and so i decided to get the LG enV (vx9900), i also decided to add the unlimited texting option for 10$ extra. so my question is... Since the enV has AIM, and the messages i send and recieve count towards my texts (or so i have been told), are their any fees i should be worrying about while using AIM or MSN from my enV??

I did do a couple of searches on google and such, and answers i got were "no theres no charges" or "Im not too sure" so im kinda looking for a definite answer. Ive been using t-mobile prepaid and just switched over to Verizon.

And yea i was pretty happy at the time about getting my new phone i didn't bother to ask my sales rep all of there right there

Thanks in advanced