Welcome to the DIS and to pin trading.
To answer your questions. Currently only the Disney Gallery Stores sell the Magical Moments pins. Unfortunately there are only about 15 of these stores around the country, but lucky for you there are three in NJ, 1 in Philadelphia, and one in NYC. The Disney Stores will soon be selling a pin series in honor of Walt Disney's 100th birthday. The pins available at the theme parks are not available at the Disney Stores, but they sometimes end up in clearance outlets.
As for other websites on pintrading, dizpins.com is a good site for news about Disney pins, and pinpics.com is an excellent database of Disney pins. Both are unofficial sites run by our fellow collectors. Tomart had a Disney pin catalog at the Epcot Pin Event that I'm sure will be on newsstands soon. I didn't get a good look at it so I'm not sure if it was a price guide as well.
There are web sites out there where pins are sold. DIS posting rules prohibit the posting of links to for profit sites, so we do ask that anyone who wants to help a budding pin addict -- er, collector

-- please e-mail him directly.
BTW, does the pkd in your name stand for Paramount's Kings Dominion? Just curious.