I was recently involved in running a webchat – a live online exchange of questions and answers in text format.
This particular webchat was between Andrew Lansley, Secretary of State for Health, and the general public. The topic was the new Information Strategy and Choice consultations, and the chat lasted for just less than an hour.
We used Coveritlive as the platform, which was reasonably successful and participants seemed to be generally pleased with the opportunity to put their questions direct to Andrew Lansley.

Not perfect, but a cost-effective way to deliver a webchat

You can see a full Prezi about the event here:

http://prezi.com/bin/preziloader.swf