(Tongue planted in cheek) Move to Spain?!?!?! You're already in San Pedro!
Seriously, I have/had similar thoughts over the last few years and I think really the best answer is a combination of some formal or semi-formal (tapes, CD's etc) courses plus, and most importantly, practice! I have done the CD thing too, but you lose it very quickly and the pronunciation is really hard to perfect. And that completely disregards the dozens if not hundreds of unique dialects and variations within each major language family.
Most likely you know bilingual or even Spanish-speaking only people who will humour your efforts. I agree it is not easy for most people beyond childhood to pick up new languages. I am trying to steer our son towards at least a working knowledge of Spanish, given where we live.