Ok this is sort of a shameless plug, but I think this site is cool so here it goes.
Livemocha is a language learning site. Higher course levels cost money, but basic levels are free. The courses are like worse versions of Rosetta Stone. However the best part of the site is that there are exercises that have to be rated and graded by native speakers of the language, and as long as you are helpful you are matched with other helpful graders. This is absolutely free of charge.
On top of that you can find native speakers who speak the language you want to learn. Because they are on a language learning site, they are more inclined to work with someone who does not speak well!
Check out the site, if you sign up cite rividzATgmailDOTcom as a referral if you can.
My profile: http://www.livemocha.com/profiles/view/4388194