I would encourage you to consider Gameboy translation, actually. Gameboy is, in general, easier to deal with than NES or SNES, plus there are a lot more untranslated games to choose from, so your final product has a better chance of being decent quality.
As for tutorials, I wrote one called The Definitive Guide to ROM Hacking for Complete Beginners that several people have told me was quite helpful. It's a bit outdated now, as far as which programs it recommends, but a lot of the information is still useful.
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