Heisig.
That said, I didn't use either; it's just that I've heard more success stories with the former. If you're up for the "fun but possibly slower" route, find yourself a bunch (100+) of Japanese song and study all the kanji you can pluck out of the lyrics. Singing along really helps. Once you've got enough down, repeat with other media (novel, manga, newspaper/magazine article, etc.)
Use Kodansha Kanji Learner's Dictionary (pirateable but worth buying) and/or kanji by parts
http://jisho.org/kanji/radicals/ to look things up.