To start with, I am working on Italian and C.C. is working on German. (C.C. is already fluent in French and, I can speak French proficiently with a bit of German). We use Duolingo, a FREE interactive language learning website. Warning: It is highly addicting and may or may not cause you to learn Spanish instead of study for exams.
It's also great if you like to see instant progress. It allows you to track the words you learn and measures your learning in different levels. Additionally, if you sign up with facebook, you can follow your friends' progress and language levels. This means I can see when C.C. is procrastinating.
My overall review is that it's a nice way to learn. Instead of learning grammar based on rules, you learn how to speak based on context and repetition. There are also a variety of languages to choose from to keep things interesting. However, you have to move through some seldom used phrases to get to the useful phrases. For example, you will learn how to say " I eat an apple" in every language to start with.
I eat an apple.
Je mange une pomme.
Yo como una manzana.
Ich esse einen Apfel.
Io mangio una mela.
Try it. Let us know what you think. Are there any other resources you recommend to learn languages? We'll keep you posted on our progess :)