There used to be a couple of decent ones. Folks stopped coming around and posting, though, so the forums have gone.
I don't know if you'll find a one-stop shop anywhere. As for basics, I gotta agree with Flintlock's approach. It helps to start with patterns in other, easier to work with materials, and to take as literal an approach as possible, when needed. 'I need THIS shape...' is often a good place to start. Don't think of it as 'what it is' just concentrate on the shapes.
As for technique, it doesn't hurt to look into how others work: woodworking, machining, even kit-builders' skills... it all helps. Working with plastic, resin, metal... yeah, I hope people jump in with tips, sites.
I think one thing folks underestimate is the need for vises, grips, 'extra hands'... and learning about armatures too. Each can prevent a lot of headaches. You don't need the ultimate set of tools, but a good basic set and supports are a must.
Scoring and snapping, how to create solid joins, when to putty, how to back-fill an area to sand it... it all comes out of necessity. Obvious thought: get building and you'll learn and yeah, the 'lessons' sometimes suck. Measure twice, cut once.
Resin and rubber will save you time and $$$. Hopefully someone here will be able to jump in with thoughts on different techniques. Scratch-building some intricate bit once can be a fun challenge... ten times, not so much.
Does anyone have any solid leads?
EDIT: as a bit of an afterthought... yahoo groups and such tend to be hammered by spam and general crap, but has anyone thought of or come across something akin to a blogspot page for sharing this kind of info?