Whiteboard linkage models
Prof. A. J. Klein Breteler maintains an array of mechanism models at TU-Delft. Access videos of these models at the site: http://wbmttt.tudelft.nl/cadom/Models/Index.htm
Animations of linkage movement.
Prof. A. J. Klein Breteler maintains an array of mechanism models at TU-Delft. Access videos of these models at the site: http://wbmttt.tudelft.nl/cadom/Models/Index.htm
This articulated model horse is by the artist James Watt.

A kit for this device and other designs can be found on his web-site: http://clockworkrobot.com/
Joseph Klann provides a useful comparison of the leg designs for his Mondo Spider and Theo Jansen’s Strandbeest at the link:
http://www.mechanicalspider.com/comparison.html
Here is a walking machine called the Mondo Spider:

The leg of this walking machine is described in US Patent 6,260,862 awarded to Joseph Klann. Access it through the link:
http://www.google.com/patents/about?id=70YHAAAAEBAJ&dq=6,260,862
Wikipedia calls this the Klann linkage described here:
http://en.wikipedia.org/wiki/Klann_Linkage
The leg of the mondo spider has the topology known as a Stephenson six-bar.
Theo Jansen builds amazing walking machines as can be seen in this video:
Each leg is an eight-bar linkage. The Wolfram Demonstration Project models this linkage in a Mathematica notebook. See the link:
http://demonstrations.wolfram.com/ATheoJansenWalkingLinkage/