HI,
I am new to development for the I phones and got the iphone from USA which is locked to at&t, i have successfully able to develop the apps on it, while it is not unlocked, now i want to unlock it so that i can use it with my local network and also wants to continue the development on it, so is it possible to continue the development on the jailblroken phones for the app store, and what problems may i encounter.
I have a first generation american iPhone that is jailbroken and works with my local network. I had no problem deploying a self made app to my phone. At the time writing I have iPhone OS 2.1. I haven't yet gone through the process of submitting the application to AppStore.
As long as the application is developed using accepted Apple practices (using the official iPhone SDK, and not open-toolchain or something like that) and does not use any private APIs, you should not have any trouble submitting an application just because you tested it on a jailbroken (or carrier unlocked) phone.
To be 100% accurate, jailbreaking and carrier unlocking are against the developer agreement, but I can't really imagine the circumstances that would lead to you being caught.