I came across this lovely presentation from Yilbu after Stephanie commented here. Great stuff, beautifully presented: "Creating ‘Casual’ Games, Content and Applications for the (Mobile) Long Tail"
And on the subject of mobile play, Mr Jones has an article in the latest Receiver mag: "...in play we explore, try new things and push our limits more than in any other state. The practice of experience design often tries to prescribe set paths for the end-user of the device, rather than allow the frustrations of a free exploration of the system. What would it mean to create truly playful space in our systems, services and devices?"