I have been using Experts Exchange for approximately a 1.5 years now and I have been very pleased. It is a support community for software development, database design, database administration and more. Some of the channels cover software applications such as Quark, Word, Excel, etc. Other channels focus on server technologies such as SQL, Exchange, MySQL, etc.
For $9.99 per month (discounted when purchased as an annual subscription) it has been a great value. The way it works is as a paying member you are entitled to post unlimited questions to any channels. You assign a point value to your question and accept the best answer. Accepting an answer awards the points to the expert. The points experts earn can be used to ask questions instead of paying for a subscription. With an subscription you are able to search all of the questions and answers aswell.
I have used the site to get assistance with Visual Basic programming questions, MS Access and SQL questions and much more. I would definately recommend this site and service to anyone.