There are a number of resources online, including the competing Pinpics.com / Pintalk.com and Disneypinplace.com / Disneypinforum.com. Both Pinpics and DPP are databases of pins (pinpics being older; dpp up-and-coming). Disney Pin Forum seems to be the most popular of the Disney pin groups, Pintalk is the official Pinpics forum. there is also facebook pin groups.
And depending on where you are located, there are local pin meets.