Best for : French, German, Spanish, Italian.
The BBC has high end dedicated language resources, with comprehensive online courses in French, German, Spanish and Italian, from beginner to advanced, as well as a multitude of learning resources for others.
Materials include language oriented soap operas and dramas, and mini learning games/puzzles, as well as more serious grammar tools. In short, it's an excellent resource.
Languages: All main European and many others
Format: Multi-format. Text, audio and video plus interactive games.
Link: BBC Languages
Best for: Interactive learning with native speakers.
LiveMocha's a clever idea which uses the power of the web to put language learners in touch with native speakers. It offers various courses which can be taken at your own pace, using plenty of interactive materials to teach.
Most important though is the innovative social networking element, which means you can befriend and help others towards their goal at the same time as they help you. Feedback for the site's excellent, and more languages will be added in due course, so it's definitely one to watch.
Languages: Mainly European, more to follow.
Format: Multi-format. Text, audio and video, plus webchat & instant messaging.
Link: LiveMocha
Best for: University-level course materials.
The Massachusetts Institute of Technology prides itself on making its course materials available to everyone, which is a boon for non-students, as some of them are excellent. If you're comfortable learning in an academic style, then there's lots to choose from; as well as straight language courses, there are plenty on local cultures to round off your knowledge.
Many languages are covered, and the site's free and open to all, though will accept donations towards its upkeep.
Languages: Worldwide at varying levels.
Format: Mostly text, some audio & video depending on course.
Link: MIT OpenCourseWare Languages
Best for: Straightforward German, French, Spanish.
The Open University's online offering lacks the range of the MIT site above, but makes up for it with simple-to-navigate, detailed courses in German, French and Spanish. The site tests you as you go, and uses audio & video to improve comprehension throughout.
Some modules also focus on the interplay between cultures and languages, to bring your social knowledge up to scratch at the same time as your grammar.
Languages: Mainly German, French, Spanish.
Format: Multi-format inc. interactive tests.
Link: Open University LearningSpace
Best for: mp3 fanatics.
There are now thousands of freely downloadable language podcasts, so finding one's usually easier than choosing one that fits. If you like the idea of learning through your headphones on your daily commute, web media directory Open Culture has an A-Z list of (mostly iTunes) language podcasts.
For more range, and especially if you don't use iTunes, just search for 'learn' plus the language of your choice on directories The Podcast Directory and PodcastAlley and you'll likely return lots of results. If you find a particularly good one, then please post its details in the forum to help others decide.
Languages: Worldwide.
Format: Audio (though many podcasts have accompanying websites).
Link: Open Culture, The Podcast Directory, PodcastAlley
Best for: Quick Conversational Skills.
BYKI Lite's a downloadable tool which aims to improve conversational skills by teaching quickfire bitesized phrases. The software monitors responses and adapts itself to suit the learner. It's also fully customizable, and it's available in a pretty impressive 63 languages.
Whilst the Lite version of BYKI is free, and is quite comprehensive, it costs £30 to upgrade to the 'Deluxe' version, which adds more features, extra lists of words/phrases, and a database of downloadable mp3s. Thanks to MoneySaver carrie_grace for suggesting this one!
Languages: Worldwide.
Format: Interactive Audio, Text & Pictures.
Link: BYKI Lite