Here are a couple of great links from Dr. Mike's Twitter feed.
Vitamin D and Cancer: http://www.youtube.com/watch?v=3GM0CnO6-ds
Vitamin D Dosage Safety: http://www.annalsofepidemiology.org/...039-8/abstract
Also check out this recent newsletter from Dr. Cannell. The first question about how vitamin d produced in the skin can be washed off is fascinating.