AJAX Chat Interface for .NET game

We have a .NET (VB) based multiplayer game with an old chat system loading chat info from a database. We need to revamp this to a better, more efficient system. The chat is divided into four parts: Chat with people in your location, chat with people on your team, chat with people on your IM (friends list), and system messages. We need a cool interface that slides up or down with a button, and then the chat should happen asynchronously, without having to refresh, AJAX and jQUery can be used, but other suggestions are welcome. We also need to build in a friends list, and a system that shows the presence of friends in the game and a list of pepole in the current location. Having experience building chat interfaces is neccessary, please show us similar past work, or a sample of what you can do for us.