I need someones help with att service!!!!! anyone who knowa about att plans please answer !?

ok, so im gonna buy the red blackjack II and i wanna get unlimited internet, so i can check myspace and other websites... also use AIM ( i dont really text, just aim chat) so how much would unlimited internet and aim messenger cost on my phone? ..................................... ive looked at the rate plans but theres quite a few so idk which is which