In my Quest for Oneness with the Universe, I recently stumbled upon some very new and very useful resources on the WWW. They are an Open Source book and a software sim. The free e-book can be downloaded from
and the software sim is found at
http://sourceforge.net/projects/circuit/
and the author of the e-book, George Self, maintains this site to support is college class he teaches
http://www.digilogwiki.com/index.php?title=Foundations_of_Digital_Logic
Happy Trails