This is a relatively new website, I think. There aren't that many people on there yet, and not too many options to choose from as far as language lessons go (German, English, Spanish, French, Hindi, and Chinese), but it'll probably grow.
EDIT: Now they have Icelandic, Italian, Japanese, Brazilian Portuguese, and Russian. After spending so much time on this website I've also noticed the lessons have a lot of odd mistakes.
It's like MySpace for language learners/enthusiasts...
There is no forum from what I've seen, only private messages and chat.
LivemochaThe cool thing about this place is they have online session for each language, for levels or "phases" that make up 160 hours of material altogether, and the courses themselves basically mimic Rosetta Stone's method, where they show you images, you hear the word/sentence and have to pick, etc. You have the option of translating everything though, and people can comment and leave advice, etc.