I found the following articles very good well explained walkthrough for creating a custom button in WPF or Silverlight:
I am back from REMIX09 conference in Sydney. Number of impressive presentations including Microsoft Surface, IE8, and strong emphasize on Silverlight.
It was announed during the conference that the videos of sessions publicly will be available on http://www.microsoft.com/australia/remix.
Other advertised useful websites:
WindowMobile (http://developer.windowsmobile.com/): to publish apps for Windows Mobile 6.X on the market place
SilverZine (http://silverzine.com/tutorials/): useful tutorials about expression blend and Silverlight.