With inspiration from stackoverflow.com, doctype is the Q&A site for web designers. Of course they're better able to describe themselves:
Doctype is a free question and answer site for web designers. You can get fast solutions to your CSS, HTML, web design and email design problems.
For each question, Doctype can generate screenshots of your design on any browser or email client. This makes it much easier for other people to see the problem and help you fix it.