“Cyclists fare best when they act and are treated as drivers of vehicles.” –John Forrester
This video by Brian D’Souza and Dan Gutierrez shows how, and why:
The discussion following this video on YouTube is well worth reading too, as it covers both California and Virginia law about lane position.
D’Souza and Gutierrez are doing great work with their Dual Chase View (TM) video technique. You can see some of their other videos at CyclistView, along with powerpoint presentations, and other bike safety training materials.