http://www.grapplearts.com/weblog.htm and you can sign up to his email lessons that go with the Roadmap for BJJ package here http://www.beginningbjj.com
Also, check out Roy Harris' article series called "Analysis of Brazilian Jiu Jitsu".
Head Coach at Leicester Shootfighters
Sponsored by Caged Steel and Empire Fight Shop
Also well worth checking out are:
Roy Dean BJJ Blue Belt Requirements
Roy Harris BJJ 201 - lots of stuff about eliminating minor errors in your game.
Specialist treatment of sporting injuries