[i am yujin]

Is there any way to clone a version of AIM so you can have 2 screennames on at once with using the official version of AIM?

Don't mention about AIM clones like Adium and stuff, I already know about them.

[King Bob On The Cob]

Yep.
File>Duplicate
Then right click and select show package contents.
Open Contents
Open PkgInfo in some sort of text editor and change the last four letters to something else.
Save.
Open your new AIM.
Have Fun!