Adium 1.3.10 is cool in a variety of ways. This is pretty much the iMac (all in one) of instant messaging, choosing from Faceboo, Yahoo, Jabber, MSN upon many more. Where you can benifit from this is in a few ways, if you hate running TenFourFox to access facebook chat or it is slow, this is a good reason to use Adium. If you would like to have your multiple IM accounts in one program where you can access them immediately, this is a great solution!
I tried using it with facebook, and unfortunally I kept getting a prompt asking for my password. So let us know if Adium works for you! This was tested with Leopard. Download here