A major annoyance with iOS is that the App Store closes immediately after downloading an application. You can’t queue multiple apps to install in bulk, and it’s unlikely that Apple will change this anytime soon.
StayOpened, a tweak available in Cydia, keeps the App Store from closing after you download an app and allows it to quietly install in the background. It’s the next best thing to a native queueing system, and at the low-low price of free, will make an excellent addition to any jailbroken phone. Just search for “StayOpened” on Cydia.