Spanish can get overly complicated with the grammar.
Anyhow, the best way to learn a language is to practice it constantly. Only sitting around with a textbook learning words won't cut it. Although that will help you learn the basic grammar and vocabulary, if you really want to learn it you have to find someone who can speak it and practice the hell outta it.
I dunno much about Rosetta stone (I want to get it to learn Dutch... I suck at being a Dutchman >.<) but I tried a demo and it worked a bit because you can listen and speak into a mic.
After you learn Spanish, it's going to be way easier learning a third language. So if you want to impress people you can do that. 
I can speak Spanish and English, so German is going fairly easy in school for me. I can speak as well as a 3 year old. 
Tag (Courtesy of Fkusumot) "If I'm posting in this thread then it's probally a spam thread."
