Project Amy integrates with Messages for Mac

The people you follow will be shown in your buddy list. Double clicking one will open a new chat window and start a new private messaging session like you would see on Omega. Sending and receiving messages happen very fast, usually within a second. You can drag files into the chat window, and they will upload to your account’s file storage and be sent as part of a message.

I haven’t tried it yet, but it sounds interesting.