Joe Hewitt, the developer who saw the Facebook App for iPhone and iPod touch to version 3.0, and the cusp of 3.1 (which promised/threatened push notifications), has thrown us the Twitter-equivalent of a curve-ball:

Time for me to try something new. I’ve handed the Facebook iPhone app off to another engineer, and I’m onto a new project.

Just to be clear, he’s staying with Facebook, just no longer working on their iPhone app. Does it have anything to do with his dissatisfaction with the iTunes App Store approval process?

According to the quote he gave TechCrunch, it did:

My decision to stop iPhone development has had everything to do with Apple’s policies. I respect their right to manage their platform however they want, however I am philosophically opposed to the existence of their review process. I am very concerned that they are setting a horrible precedent for other software platforms, and soon gatekeepers will start infesting the lives of every software developer. The web is still unrestricted and free, and so I am returning to my roots as a web developer. In the long term, I would like to be able to say that I helped to make the web the best mobile platform available, rather than being part of the transition to a world where every developer must go through a middleman to get their software in the hands of users.”

Hewitt’s move is a big deal, because he has essentially been the one-man show behind the iPhone’s most popular application of all time. Hewitt has been quite vocal about his opposition to Apple’s ridiculous App Store approval policies — in a post last August, he wrote that “the review process needs to be eliminated completely.” And to be clear, Hewitt is still at Facebook, though he can’t talk about the next project he’s working on.

Hewitt joined Facebook in 2007 when it aquired Parakey, the company he co-founded with Blake Ross. Hewitt is also known for helping create the Firefox web browser as well as the popular Firebug development plug-in.