The organising body of Formula One have offered this service for a while but I have only just got round to bloging about it. During all F1 sessions including the race live timing is available in exactly the same format as is available to the teams.
This means that even when the Williams are not on the screen (which these days is often) I can still see how they are doing relative to the rest of the pack. There is a great level of detail as you can see from the screen capture above including gaps, pit stops made etc. All of which is free. If you are into F1 it is an essential service. Check it out at www.formula1.com