Rocketry

Possibly the only website you will need! can be a bit technical.

http://www.grc.nasa.gov/WWW/K-12/rocket/shortr.html

http://www.grc.nasa.gov/WWW/K-12/rocket/bgmr.html

A Rocketry resource website

http://www.ukrocketry.com/index.html

United Kingdom Rocketry Association (UKRA)

http://www.ukra.org.uk/