I liked Reddit's system. Click on a prominent "feedback" link (in the early Reddit it was in the top left, and one of the most prominent actions on the page), it takes you to a page with a textbox that e-mails the founders. I submitted a couple bug reports to Reddit when it was a few months old and got back fixes within the hour, which was one of the main reasons I decided to stick around.

Also, don't underestimate the usefulness of forums. They become a pain to manage when you get big, but they're absolutely invaluable at getting feedback and building community when you're small. Forums let power-users help newbies (pulling some of the support load off you), and they also give users a chance to weigh in with "No, that's a terrible idea" when another user proposes a half-baked idea. When I was working on FictionAlley, there were many times when a user came up with a suggestion, I was like "Yeah, I can implement that", then other users chimed in with "Please don't; it'll ruin things for the rest of us. Here's what you could try instead."