If you are to start up your own writing group, here are some suggestions.
Usually, Borders, Barnes and Nobles, or a local library has no problems hosting and they will often advertise for you by putting your writing group in their calendar of events.
Pick a convenient time, i've found the 7:30pm - 9:30pm on Tuesday, Wednesday, or Thursday seems to be the universal best time to host a writer's group as it accomodates most people's work schedule.
Print up fliers and distribute around town: namely bookstores, libraries, and college campuses (most places have no problems letting you advertise your writing group).
Format wise, most writing groups i've belonged to start off with 5 - 10 minutes worth of quick writing exercises where we'd write to prompts, then afterwards we'd read what we wrote from the prompts. Once that was done we'd move on to critique works people brought in but usually limiting that to a few pages each.
Another route that worked well for smaller groups was bringing in longer works that we'd read/critique on our own time and then came to the group ready to discuss.
There are lots of writing prompts available on the internet, do a quick google search.
After a couple of weeks, you usually have enough people to keep a group going indefinitely.
You can also advertise (for free) on Craigslist.
I've found that as long as you live in a town of 50 thousand or more, getting a writer's group going is no problem and easier than you'd think.
You may even be able to contact nanowrimo and ask them to send out an email invite to writer's in your area.
Anyways, good luck
Mel...