There are CMs throughout the parks, resorts, and DTD with lanyards. You can trade any copyrighted Disney pin for any pin on their lanyards.
During the day, you may find people to trade with at Pintraders in DTD, at Epcot Pin Central, or at Expo Hall in MK. But it's kind of hit or miss. If there is a release schedule for an LE pin, it is more likely to find people around.
In the evening, you will always find traders at DTD -- but beware that this is a "sharkey" crowd.
There are regular WDW sponsored pin meets, every week: Thursday night at All Star Sports, and Friday night at the Contemporary.
There is also a fairly regular weekly pinmeet on Saturday night at Riverside.
Hope this helps.
