I don't know anything about the "Big Brother monitor suite", but I imagine there might be a way to provide initialization code that's run when your module is loaded? If so, connect in there and have the message handler use the Net::AIM object you created in the init. Or, have the message handler connect if there isn't a Net::AIM object already, and then pass that object around where/when-ever you need it.
Anyway, seeing some code or a better description of how the process works for Big Brother might make for better answers.