I recently gave an hour long webinar on casual game design for the International Game Developers Association. The talk touched on some of the ground I cover in my book, "Casual Game Design." (http://bit.ly/aFDxd7) I also gave a very brief analysis of some of the design decisions that informed our iPhone Gigaputt. The slides provide a visual guide to the ideas illustrated in the talk (though they make much more sense with the audio). If I can get the audio from the IGDA I will post it here as well.
In the presentation I try to define casual games and define some defining characteristics of casual play. I also touch on the importance of developing a mental model to explain games before going into the process of being a game designer. After laying this initial groundwork I look at some specific games and the mechanics that comprise the gameplay.