I showed off some of this tech during my presentation @ Tech Ed Auckland this year and have had a few questions on it so here are some pointers to get you going. You have a few options for updating your smart client apps.

• ClickOnce
  Not coming until VS2k5.
  Take a look at MSDN TV: Introducing ClickOnce: Web Deployment for Windows Forms ...
  and ClickOnce: Deploy and Update Your Smart Client Projects
• Updater Application Block
  Works with the current technology. Very flexible but hard(ish) to implement.
  Go here patterns & practices: Updater Application Block: Home
• Application Updater Component
  Easy to implement- this is the one I used for my Demo which if you remember took me about 5 minutes! See here.NET Application Updater Component and also TaskVision  for a good example of it in use.