I know some people here have tried dating sites - OK Cupid is popular. I just joined it, very recently - no luck yet but I met another poly woman there who has had some luck with the site. The nice part there is that you can write that you're poly in your profile, and not have to worry about when to bring it up.
Keira Raven, married to husband Mal, interested in a woman for a triad or vee
(Previously known as Dakota Raven, husband previously known as Adam)