Read through the above links thoroughly. Then come back and ask questions. These are both awesome resources to new users, and many users have asked many of the exact same questions you'd like to ask.
You need to develop a general understanding of both the Android operating system and the methodology and tools used by "hackers" to enhance their phones. Once you get this knowledge, questions are more direct and specific.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?