Carl and Richard talk to Wally McClure about building mobile applications for iPhone and Android using MonoTouch and Mono for Android (respectively). The conversation starts out with Wally's original interest in the Mono tools, being able to leverage his code and skills in C# for mobile development. From there Wally drills into the challenges of tooling across platforms (testing frameworks, etc) as well as dealing with fragmentation of operating systems and SDKs - a bigger issue in Android than iOS, but still an issue.