The new (January, 2008) issue of Road & Track mag has an article "The Evolution of Safety Technology in Motor Racing." The first 2/3rd of the piece deals with F1. It is mostly Prof. Sid Watkins talking about the changes since the deaths of Senna and Ratzenberger back in 1994. He also talks about Kubica's Montreal shunt, and how those changes helped save him.
He deals with everything from crash testing to the HANS device to the new 8600 standard helmets. One thing I hadn't heard of is that in 2008, they hope to have accelerometers fitted into every driver's radio earplugs. This will give them accurate info on the g-loads in any impacts they have.
He finishes with this quote: "We've been blessed, really. Although we've had some big accidents, nobody's really been hurt since 1994. We keep trying to improve safety."
Prof. Sid was made race doctor in 1978. He retired 26 years later, in 2004, as FIA F1 Medical Delegate and Safety Delegate. He is now President of the FIA Institute of Motor Sport Safety.
The last third of the article is about how Dale Earnhardt, Sr's death at Daytona in 2001 brought about safety changes in NASCAR.