We've only a few folk here so far. I'll recommend trying to find a local group, if such exists. Another option is to hang out a shingle on a poly-friendly personals site. OKCupid is poly-friendly; it does require each profile to be of one person, so a couple will have to have two profiles.
I don't recall what other personals sites I'd classify as poly-friendly. I made a list a while back, though I can't find it now.