Seems like the iPhone/iPod have helped to double the mobile games development share, from its previous 12 percent to its current 25. That is, of the game developers out there, previously 12% were developing for mobile platforms, while now 25% are doing the same. 19% of all game developers are currently developing for the platform, which is apparently two times higher than either the DS or PSP developer pool.

Source: http://www.electronista.com/articles/10/02/05/apple.catching.up.to.nintendo.in.dev.interest/

Getting the developers on board is a good way to get more customers on board. And if the developers are on board it means there's some money to be made.