ePeople
http://www.epeople.com/

"An open marketplace where IT buyers who need help are matched with IT service providers who can deliver it"

The site connects customers to experts or service companies. It checks certification of sellers who apply to join the list. Buyers can set up an account or just walk in online. Sellers use software to view the customer's machine and step him through a solution.

Buyers submit questions and view the incoming bids and the ratings of the sellers.

This site's not for casual surfers. There's no public archive of answered questions. You don't see a list of the sellers or their the ratings until they bid to respond to your question.

The customer pays online when he's satisfied and the site pays the expert by check.