There are plenty of excellent resources available specific to public skatepark development.  Here’s a couple we highly recommend.

Skaters for Public Skateparks
This is a worldwide non-profit group based out of the Pacific Northwest dedicated to public skatepark development.  Skatepark advocates and builders can share information via forums on a variety of topics pertinent to public skateparks such as vision, advocacy, fundraising, management and DIY (do-it-yourself.)

The Tony Hawk Foundation
The Birdman is helping communities make their skatepark projects reality by rewarding grant money to those willing to work hard for what they want.  Good information on the positive impact of skateparks on America’s youth.