As I said, leaks are increasing as we approach WWDC '09. Engadget now says that a "trusted source" claims 4, 8, 16, and 32GB iPhones. "If true," Chris says, "this would lend credence to the belief that Apple will be introducing at least two new models this summer."
Engadget's trusted source claims that the iPhones have been approved by the PCS Type Review Certification Board, which certifies models for use with some carriers. Chris points out that this may open the way for a sub-$100 model.