In case you're fortunate enough to be going to TechEd Europe 2006, be sure to check out the various partners and presentations related to extending Visual Studio while you're there! I won't be present in Barcelona, but several other members of the Visual Studio SDK team will be around the exhibition floor and presenting various sessions.
I'll be presenting at the VSIP developer lab here in Redmond in a few weeks. The upcoming lab will have a heavy focus on Visual Studio Team System extensibility, but the SDK team will be around to help answer any questions you have. Hope to see you there!