Leaded Gasoline?

I was reading one of my car magazines and I just happened to notice that they state that the recommended fuel to be either "unleaded regular", "unleaded mid-grade", or "unleaded premium". As they haven't sold leaded gas up here in Canada since I think the mid to late 70's(maybe early 80's?) I was wondering if they still sell it in the US. I just did a little research and I see that leaded gasoline is still being used in racing cars as allowed by the Canadian Government because of the use in the US at racing events. There is apparently leaded gas used up north.

Here is an excerpt from the Canada Gazette that is the official of the Government of Canada:

Leaded gasoline production, importation and sale has been prohibited, for the most part, under the Gasoline Regulations since December 1, 1990. Approximately one million litres of leaded racing fuel were imported into Canada in 2001. This represents less than 0.01 percent of the 36 billion litres of gasoline (mostly unleaded) used annually in Canada.

The things you learn....