First, Alicia Rey of Argentina recommends Bell English, the site for the well-known language school in the UK. You have to register to get the best out of the site, but it is free. Try Telephone English, and give us your impressions in a comment.
Alicia recommends her own site, English Studio, which is a Blog packed with videoclips of authentic English, with accompanying exercises. Try it now! (and leave us a comment).
And Rossella of the Saturday 4B course sends us English Club, full of grammar explanations and exercises.
Try all these sites and don't forget to leave your comment. Your comments turn this site into a community.