IMO, the iPhone is not a Mac unless it can run arbitrary unsigned 3rd party binaries. There's no evidence it has this capability -- the iPod doesn't, and most mobile phones don't. I think Apple will offer a very limited sandbox for toy sw development (think Dashcode), and will charge a hefty sum for the certification necessary to develop real apps.

The "Made for iPod" logo program for accessory manufacturers isn't exactly free either...