Other folks have collected many more links than I. Here are some of my favorite collections and sites.

Trebuchet Sling attachment

Useful starting points for more Siege Engine information:

• dmoz: Siege Engines "dmoz" is a collaborative web directory. This directory is referenced whenever someone does a web search on Google.
• Trebuchet.com hosts Ron Toms trebuchet collections.
• The Hurl is the ultimate online message board for catapulters.
• punkinchunkin.com is the official web site of the World Championship Punkin Chunk.
• Onager.net Bob Carbo leads his band of wiley Torsion boys to many contests. This is a fine site for any aspiring siege engine builder.
• Gray Company Trebuchet Site. The ultimate online resource for historical machines, and lots of pictures of their own machines. Their links section is great.

General links and contributors to Siege-Engine.com:

• BogWorld hosts a daily cartoon about a small dinosaur named Bog. Joseph Pillsbury was kind enough to let siege-engine.com host several of his catapult oriented cartoons.
• Domain Direct is my Domain Name Registrar. I find their service to be very flexible, inexpensive, and its just cool having an email address @siege-engine.com.
• Amazon.com is an online bookstore with a nice affiliate program which makes it easy for me to recommend books.
• Source Forge hosts my Emacs Tools web site. If you know what Emacs is, then you will want to visit.
• Sewshoppe is one of my wife's online stores and current service provider for these web pages. You can learn how to make your own cloth diapers.