I'm relatively new to the developing world (I'm a systems student, currently learning Java) and am very interested in creating a simple tweak for iPhones that replaces a file in a certain folder of the device. I've done this manually, by using DiskAid to place the file onto the folder right from my computer, but am looking to create a little tweak that can be used by anyone with a jailbroken device. I'm looking to learn, so any links to tutorials, tools and such would be great. I own an iPhone 4 and a Mac, with access to windows, so no compatibility issues there. Also, I've heard about a tool called Theos... Is it as great as people claim it is? Thanks for your time.