The famous skinner Ross Harvey AKA b0se (creator of Vectorcell, and Opulence among many others), has recently opened a forum called Web9Design. This new forum is aimed towards professional/semi-professional web developers and graphic designers (with a focus on implementing web standards).
The purpose of the forum is to build a comprehensive knowledge base and (politely) ask you to share any useful tips, tricks or tutorials you may have.

A very nice and clean forum!