[Otter74]

I can't give a recommendation of a particular method or app, but Spanish is a relatively easy langiage to learn for a native English-speaker, as pronunciations are very consistent (unlike English), there are only five vowel sounds, there aren't any difficult-to-pronounce sounds (other than perhaps rolled 'r's) and so on.

It is quite idiomatic, however, and vocabulary is significantly more regionally-specific than English. I was born in Venezuela (North American mother, Latin American father) and moved to the US after 8 years; my Spanish (which is not up to my English, thanks in part to most of my life here) reflects this. The word "chimbo", for instance, means one thing in Venezuela and the opposite in Colombia, and it means nothing in Mexico; slang in particular is extremely local. Foods can have four or five different names just in this hemisphere (e.g. banana can be cambur, guineo, banana, platano) You're best off learning whatever variety of Spanish you're most exposed to where you live. As one who grew up speaking and listening to Caracas and costeņo Colombian accents, I find Castilian (e.g. Madrid) accents and speech, such as many US students learn, rather odd-sounding. And I find voseo especially odd-sounding, as most of Latin America doesn't really use it and I never grew up with it.