A lot of hate going to a person trying to learn. I have a developer account, which I have used to sign my own code for purpose of testing it on real hardware. People could put guides like this out on the internet anonymously, if they have id be happy to read em.If you are a developer, then you know that your use of your account is subject to non-disclosure agreements which would preclude publication of this information. I'm sorry, but they're not going to jeopardize their dev accounts so some newbie can jailbreak his phone a little early.
If you are indeed a coder, then you should already know the basics for finding bugs to crash the system and exploit the code. There is also this great thing called Google search.
Of course, of course, you create a piece of code that would make a buffer overflow. I don't know how to inject code, or the full extent of what to inject when I have an opening like that. I have been searching around, if you can give me a few heads up about search terms to use to find this id be really glad.