We are perhaps at a bit of a juncture. MobileBeat claims HTML5 will kill the native app. It may, but that may not be something a beginning programmer needs to worry about. I think it is enough that the technology is popular, current, and growing. It's a good start.
Jochen Voss gives a quick overview in How to Write an HTML5 App?
Google "HTML5 tutorial" and "learning HTML5" for the latest, best, pages.