Not sure if it was mentioned before... but I just had to comment about this...
I used an amazing system to learn Spanish. In fact, it was enough to arrive in Chile with intermediate level Espaņol! No classes, no spending money on teachers, no forcing myself to sit in front of a computer and learn vocabulary.
Check out
www.radiolingua.comI listened to Coffee Break Spanish and Show Time Spanish over and over. Yes it's a podcast (you can also search for it on itunes). It's free unless you want the extra stuff it comes with, but the basic version was enough for me. I listened to it on the way to work every morning for about a year, but even if you don't have as much time you will find that you pick up a lot. The lessons are at a good pace for both beginners (Coffee Break) and intermediate speakers (Show Time).
I now live in Chile as part of my immersion experience and even managed to find a full time job in my profession!
Buena suerte a todos!