instant messaging on nokia 7610 ?

hi i was just wondering how i can do this and how it works?

i have just bought this fone off ebay fairly cheap i know its not the latest but i like it and £50 for the handset leads software 64mb memry card as well as an extra 356mb memry card, you can't complain.. well i can't =]

so yeah i was just wondering how i can use instant messaging on it and what software i need and is there any free versions as i have done a google search on it and found many programs that you need a license for.

anybody tell me how it works / the cost of using it e.g. wap cahrges or any similar cahrges?

thanks

chris