Logic Gates using Toys (time: 2:37)
This is one of the best all around
sites that I have found. It is titled "The MacTutor History
of Mathematics Archive."
This is an award-winning
site that links to all sorts of mathematics information.
This site presents an interesting logic
These sites considers
logic gates (with links to other logic topics):
This site, Basic Gates and Functions,
provides a nice discussion of logic circuits: