If you are looking for a fun, relaxed and sociable way to learn a new language, then LiveMocha is an excellent choice.
What makes this language course stand out from others currently on the market is the fact that it relies on the input of an online community. There is no software to install on your computer here - instead you are given a subscription code and four good quality books for use as a point of reference. Once registered on livemocha.com, all of the lessons from your chosen language course are available online for you to complete at your own pace.
The exercises on offer provide a good selection of activities, ranging from simple "fill in the gaps" tasks to more complex oral dialogues. The interface is also very user-friendly - the units for each lesson are all clearly laid out and the exercises themselves contain pictures and recordings in order to help you further.
The unique selling point of LiveMocha however, is its online community. At the end of most lessons you are required to complete a short written and/or spoken exercise, which you then submit online. Once posted on the website, other users (often native speakers of your chosen language) provide you with helpful feedback on your exercise, correcting you and giving you useful advice in order to improve. I have found this aspect of the course very helpful indeed - within minutes of me submitting an exercise, I receive on average between five and seven comments, the vast majority of which are incredibly constructive. It's really encouraging to have native speakers tell you "Well done!" or "Keep up the good work!", and as such Livemocha's social dimension gives it a key advantage over its competitors. How much you integrate into this social aspect though is down to you - if you so choose, you can create a Facebook-style profile page for yourself and add specific friends with whom you can exchange exercises. This isn't compulsory, but is recommended. Furthermore, if you pay extra you can have your work marked by a qualified tutor in order to take your learning to an even higher level.
There are a couple of problems with this specific course though. The first is that it is South American Spanish as opposed to European Spanish. The variances between the two aren't massive, but there are a number of subtle differences so be aware of this as the product description does not make it clear. In addition, the course makes significant use of recorded dialogue exercises, yet doesn't come packaged with a microphone. True, most modern computers have an internal mic anyway, but if you didn't have one I'd imagine it would be rather irritating to purchase a separate accessory in order to get the most out of the product.
LiveMocha is an excellent education tool. Of particular note is the social element, which makes your learning a lot more interactive and fun. I can't praise this idea enough and truly believe it is the future with regards to home language courses. I have tried a number of different products and approaches before and they haven't worked because I didn't find them engaging enough. Livemocha is completely different, and I highly recommend it.
One piece of advice though - courses such as this will get you to a certain level of competence in a foreign language, but to become truly confident and eventually attain fluency I would recommend taking formal lessons and visiting a country in which your language is spoken. At present I am using LiveMocha to support and consolidate what I learn in my evening classes and I believe this is one of the most effective ways in which to use such a product.