Look in a folder called
" Application Data/AIM/ " There should be a folder in that directory named <your AIM screenname> In that folder you should see a file called "userinfo.bag" Open that using "open with..." and use notepad. Its a little scrambled but you can decipher your buddly list names from it.
Also, I believe that the 'application data' folder is hidden, so you need to change your folder properties to 'show hidden files' beforehand.
Also, you should be able to do START -> SEARCH files or folders and enter that screenname.