There are a few people who swing around here, but the focus of this forum is polyamory (obviously
). Swingersboard.com is a good forum about swinging if you're interested in reading about the internal workings of that side of open, as well. Not to say you won't learn a ton from getting to know the wonderful people here, but you probably won't learn as much about sex-driven relationships.
In general, though, the concepts are similar. In both, you have to figure out what boundaries you and/or your partner have, decide what sort of situation you want to find (closed group where you're with the same people for an extended time or more open where it is a one time thing or just a few times with the same person/people or something else), what kind of people you're interested in (male, female, trans, coupled, single/solo, straight, bi, gay, etc), and make sure you know how to communicate these things to others.
And, of course, welcome to the board!