Google has launched a section in the AdWords Help Center aimed at helping small businesses improve their campaigns. It's called Small Business Corner.
"The Small Business Corner is designed to give those of you who are running your own AdWords accounts the opportunity to share best practices in discussions with your peers so that you can make sure your AdWords account is doing all it can to support your business goals," says Google's Miles Johnson. "This new category is not about troubleshooting specific account issues, but rather about sharing and learning from the experiences of others."
Johnson throws out: choosing the right tools to measure results, how to write great ads, and finding the right frequency to sign in to AdWords as topics of discussion.
There are already more topics to discuss in there, and given that AdWords are a pretty popular small business marketing tool, I'd expect this forum to get a great deal of discussion going, which should make for a very useful resource.