I've fund an interesting group if you're into the startup thing, or just building product that you'd really like to sell :
It's called http://startupguild.net/
It was launched by jason & justin from the techzing podcast (which is my favorite podcast ). It's a very nice group of people who try to build startups, you can share tips, ask for feedbacks. The group is really good and knowledgeable.
If some people are here on DC & on startupguild, may be they could signal them here too