First stop I'd say in
Michael Washington's website and blog...
One of the developers on the project and also an evangelist in the DNN field. If I can't figure something out in the system, he's the person I turn to.
There's also a paid subscription called DNNCreative which hosts a variety of articles and such.
The architecture is not really well documented, I had to get an understanding of DNN 1.0 (which sucked ass) in order to understand how they evolved to where it is today.
I'm not a guru when it comes to the system but I know it quite well. If you have any questions I'll try and respond. I need to use my knowledge of the system somehow, hehe.
Eric
'Not everything is binary, if you look closer you might find some hexadecimal in there somewhere'