i've heard good things about the Rosetta Stone computer program. it's really expensive, and i've heard for spanish there is one substantial minus: they exclude a tense from their teaching (preterite or imperfect, i think). but it's supposed to be very good for learning vocabulary.
i've been getting some reading knowledge of spanish in the past year, and so i'm just going to go with the much cheaper Instant Immersion computer program--because it's a hardcore immersion method, i've heard many say that it's not recommended for those with no prior spanish.
man, i feel for you on the german front. worst linguistic mistake of my life. have you ever met a native german-speaker who isn't also pretty darn fluent in english? welcome to a much easier (for english-speakers) and more useful language!