If you have the same AIM I do which is version 6.1.41.2 which you can find out when you click on "about AIM" then you can get the IM history under VIEW and then click SHOW LOGS.
Im trying to go in and see if this is a setting you have to enable.
It is checked yes in my settings but I dont remember if I checked it or if it came already enabled. Go to EDIT and see if it is checked in IM Logging. If not, then check it.
You can also install a keylogger program on your computer to capture all the keystrokes that are being typed. Very useful for getting kids passwords! You can go to download.com and find some free programs or free to try programs.