It's really easy and fun to use; I'm currently using it to learn italian. They have an iPhone app as well (that's what I'm using) and they have even more languages to learn (for free!) than are listed above. I highly recommend it.
The Top 9 Apps That Will Save & Make You Money -- this is a great list! I've personally used most all of these apps and would recommend them! Check it out! save money, ideas to save money, smart spending habits