I've been using this live chat solution, Zopim, on my website to chat with prospects, members and customers. It's really easy to setup and my visitors absolutely love it. I've seen quite a few sites using them for customer service as well, so I thought it'd be interesting for you to check out as a value adding service for your business.
You can sign up for their free trial here, enjoy! (BTW, for the size of our business, I only needed a free account, but the free trial lets you see what the best account is like) ;-)