A few team members have blogged about this already, but here I go again...
Unit testing is a method of testing individual software components. Each function in every class is tested to make sure it does its job correctly, with the hope that if everything works correctly by itself, higher level problems will be less common or much easier to debug. Wondering if it is right for you? Already doing it, but looking for best practices? This is your chance to chat with unit-testing experts and enthusiasts from the C# team.
Scott Nonnenberg posts some info about the chat, telling us;

You can find the description, an outlook reminder and a link to the chatroom here: http://msdn.microsoft.com/chats/#vs_mar18 (A few weeks ago I added anchors [as in #vs_mar18] to the chats page to allow folks to link directly to an individual chat... so now I just have to use it whenever possible :) )