Learn Icelandic for free online? Czech? Catalan? I know what you're thinking - an "under construction" geocities site with frames and pop-up ads. You'll be surprised. While French & Spanish students can find high quality language learning sites like BBC Languages, many less commonly studied languages also have phenomenal learning websites. I selected a few very good ones - all have nice design and lots of lessons with audio: Catalan, Polish, Esperanto, Little Czech Primer, Latvian, Tibetan, Icelandic, Dutch, Hindi, Norwegian, Serbian, Greek, Breton, Welsh, Chinook, Korean.
For more language courses for specific languages see Word2Word, I Love Languages and Single Serving. Northeastern Illinois University also has their foreign language labs audio online as mp3s.