I've been using Jabber with transports to connect to AIM using the built-in Jabber client on my N800 since February and it works fantastically for me. Just find yourself a Jabber server that supports the transports for the protocols you use, sign up and set up the transports on your computer with something like Psi before you set it up on the IT. Much less bloat than Pidgin and a lot much usable since it's built-in.