Language Garden is a beautiful site, or rather a swf application, which presents us with an interactive grammar course. It is divided into 5 levels, and has 12 units per level.
The top prioritiy is grammar, but some dialogues are recorded and there's some work on vocabulary, comprehension, writing.
All in all, a very interesting site with a poetic touch on which we must invest some time to get to know well and benefit from.
H/T to David Deubel .