Out of all the web based informational sources, I personally like
http://www.iguanaden.com for some decent and well evidenced facts. I would never recommend a single web resource as a lone source of information though.
Some of the best information I have ever gotten on iguanas came from the man who's book I quote in my signature, despite writing mostly about ants, termites and baboon troops in most of his work, the principles that Edward Wilson puts forth are of great value with any given organism you may try to keep. The understanding of the genetic basis for behavior allows you to avoid anything that says you can "train" or "tame" iguanas though. If the person writing the information fails in that basic biological principle, the remainder of their information becomes highly suspect.
I normally try to avoid iguanas, iguana related message boards and iguana owners, it's an enormous stereotype on my part but I find most of them to be among the most ignorant of reptile owners, to the point where my palms itch and I grind my teeth to nothing as they speak...
But this is a new message board, a new group of people who have shown themselves to be both educated and willing to learn what they are naive about (as I am) so I'm willing to answer iguana related questions as well.