When it came to exciting developer and user imagination, Apple's iPhone changed everything. What it change, however, was the degree of difficulty involved in cranking out iPhone applications.

• Smartphone Operating Systems: A Developer's Perspective
  by Tom Thompson
  Apple's iPhone redefined the concept of the smartphone, but isn't the only smartphone operating system out there.
  

• MonoTouch and the iPhone: The GPS and Compass Functions
  by Bryan Costanich
  Building iPhone applications using C#
  

• Porting Javascript Applications to the iPhone
  by Tom Thompson
  Tom examines the iPhone's web capabilities by porting a web-based application to the mobile device.
  

• Inside the Lab: iPhone Software Development
  by Jonathan Erickson
  Alexander Tyagulsky, coordinator of the ConceptDraw Lab Project, talks about what's involved in releasing an iPhone version of its logic game Aha!.
  

• The iPhone Application Builder
  by Bob Cusick
  Why bother writing apps for Apple's iPhone when you can write an app to write the apps.
  

• OpenGL and Mobile Devices: Round 2
  by Richard S. Wright Jr.
  OpenGL ES for the iPhone and iPod Touch