yep apple is a huge asshole and doesnt let you sync to more than one comp.
what i did was downloaded "mojo" which lets you get music from other peoples libraries through an AIM type deal. all you have to do is sign up with it on one comp with an email adress and another email adress on the other comp. its super easy and free.
shit thanks alot dude cause that mojo thing wasnt working
ya man i gave you karma