Hi Ian,
What tool do you plan to use for the chat? We may be able to use p2pu etherpad (I can ask, if you want)...
Also, we should make sure that the chat gets copied and archived somewhere, so people who can't attend it have access to the discussions. In addition, it would be great if someone could write a summary each week. Any volunteer?
Finally, at what date do you plan to start the chat?