Thanks @wptavern for the tip on Zopim.

I have just implemented the Zopim live chat wordpress plugin on ThemeJam.com. Interested to see how it impacts the readers and sales.

I have also set it up to direct chats to my AIM account. Makes it really easy to manage chats.

I also have the widget set to "hidden" when I'm signed off. I prefer to only display the widget when I'm actually available to chat with visitors.

Overall, great features and really nice WP integration.