Links

The Algorithmic Beauty of the Trebuchet, a site devoted to trebuchet mechanics and optimization
The Centre for Medieval Technology, Denmark! These people got it going on, anything medieval comes to life. Multiple trebuchets
www.trebuchet.comThis is THE site for trebuchets, wanna build one see the plans page
This is the Timberframers Guild, these men and women are very serious and worth emulation. They go through the process of construction.
This site is in French, but definately worth a look for the images.
LEGO Trebuchet page, if this needs explaining you need to grow down
Good story

Castles of Britain. This is a site dedicated to the study of castles in Britain.
Grey Company Trebuchet, an often referenced site
Non-gunpowder Artillery page, good overviews.
Deimos- trebuchet with attitude, see the holy book.
Experiments in medieval germ warfare, check out the crater
PBS online about trebuchets, light but entertaining if you got a little bit of time to kill. Game available 'Smash the Castle'
Nice journalism story about enthusiasts
Admit you watched Northern Exposure, now that we're being honest here, lets pay a visit to the page of the $50,000 siege engine featured on the show. The owner will even set it up on site for you. For a mere $50,000 OBO.