Special Interest Groups (SIGs) in your district? #edtech

Has anyone successfully created special interest groups (SIGs) for the teachers in their district? This is a project I want to try this year, but I am wondering if anyone else has tried it already. And if so, how did it turn out?

I would like to create different SIGs for specific technology topics. Like say an iPad SIG, or a collaboration SIG. The SIG could meet monthly, or every couple of months. Not so often that people get burned out, but enough that people can get regular information on the topics.

I want to run the meetings in an 'un-conference' style. Where we can run short concurrent breakout sessions which are driven by the requests of the crowd. I think we could start out with our technology specialists running the breakout sessions, but my hope would be to eventually have the teachers (and possibly students and community members) take over the presenting.

Is anyone already doing something like this? How would you feel about participating in district PD run this way?