A how to question

I am not sure if this is the right section for this question or not, but what I want to do is to open a webpage in a AOL Instant Messanger window using target=_self, so the webpage loads in a AIM window, then I also want to tag on a %n, to get the persons screen name and want to log it in a database but I dont have a clue on how to do that. The screename/username will show in the link and I dont know enough about this stuff yet on how to get info from the link into a database.