if you really are a nOob, don't attempt to emulate any systems. The only thing you will get is misery, unless you pull a Zero and copy some code. Start with some small projects and read up on system artchitecture, etc. Maybe try something simple like a rom remaner.
*edit* i don't want to discourage you, and if you have had a decent amound of programming experience, then by all means take a shot at one of these systems. however, here at emutalk i have seen way to many people with no programming experience think they can just start programming an emulator like its nothing. even the simplest of systems take a lot of work.