Is not clear to me why so many people want to have an iOS eSpeak port. All the applications built on top of such port cannot be distributed via Apple app store. May be the plan is to distribute on jailbreak iPhones.
So, you convinced me, let see what will happen. I just added the GPSpeechSynth library code on github. There is a Xcode project that generates three different static libraries. One based on eSpeak v1.44.05 (I didn't have time to update it to the latest version) and other two based on FLite 1.4
The library based on FLite 1.4 was successfully used in Math Teacher application that is now distributed by Apple. here you have the links:
UPDATE (17th Nov 2011):
I just added a working example in this repo.