The team has introduced an open source framework called Chameleon, which provides apps designed for iOS an easier porting path to run on Mac OS X as well. Most of the work came from tools built to handle Iconfactory's own apps, but they've released the code to other developers interested in reusing iOS code for Mac OS apps.
A lot of the ins and outs we'll leave for the developers to figure out (the project page admits that Apple may be working on exactly the same kind of solution, and Iconfactory says that if Apple tells them to shut it down, they will), but the bottom line for us users is that developers accustomed to creating iOS apps will have an easier time bringing those same projects over to Mac OS X. That means more quality iOS apps making the leap onto the Mac App Store, and better selection all around.
The project is far from done -- Iconfactory admits that it was really just a toolkit built for their own apps, and the code has lots of holes that the documentation doesn't cover. But they are working on it and accepting donations, and interested developers will be able to contribute as well. It sounds like an interesting project, and it should pave the way for even better apps on both platforms going forward.