The US imports more oil from Mexico then Venezuela. Wont matter for too much longer because all three are in decline (If you count the tar sand production then Canada's is flat). I heard somewhere Mexico is expected to become a net IMPORTER of oil in 4 years.
Possible. The Canadian oil supplies have been barely scratched, however. Especially the more northern and offshore deposits. This is not, of course, to say that we shouldn't be worried and should keep happily burning away the oil, blissfully ignoring the future.
So I guess rising demand and flattening supply have nothing to do with current oil prices?
Demand and supply now are influencing the projections 10 years from now, which are determining the current prices. Like I said, oil and gold prices are based entirely on speculation and projections for the future, not the here and now. The result is that oil companies make a literal killing as prices go up while their actual cost to extract the oil is currently static. It's a pretty good racket if you're on the money-making side of things.
However, while we're talking oil, the only way you're going to finance a serious attempt at an alternative energy source is through government funding, and right now too many of the Western governments are embroiled in defense spending. Dump the US DoD's funding into cold fusion research today and by 2010 we'd each have a small nuclear reactor powering our households.