I happened on http://www.mylanguageexchange.com a couple of days ago while I was searching something else, and while I’m normally skeptical about this kind of thing, it seems pretty well organized, and at least all the links and buttons work as promised!
The site is free for the “basic services”, unless you want to be able to actively contact people who are registered. If you don’t care, you can put up your profile for free and just hope that somebody will contact you. The memberships are not very expensive – I am trying one out for a year for US$12 since I had some extra change sitting in my Paypal account this month.
I have already met a good exchange partner via e-mail for my new hobby of studying Tagalog, and someone else has contacted me for another language combination. They offer options of e-mail only, text chat or voice chat, and have games and other stuff up on the site.