4 links
BMXTRIX: Building and Ramps
bmxtrix.com
Provides summaries on templates, layering materials, and over a dozen plans for various types of ramps. Free plans and downloadable templates.
Build a Modular Halfpipe
modular_halfpipe.tripod.com
Provides free instructions on how to build a halfpipe with step by step plans, photos and needed materials.
Halfpipe Pictures
rickdahlen.com
Includes photos of the steps taken in building his son's halfpipe. Also includes free plans and FAQs.
Skatepark Guide
skateparkguide.com
Resource for designing and building concrete skate parks and portable ramp kit parks. Skate park guide book and CD ROM available.