Footing Tubestm are a Canadian product highly recommended in the March 2005 Fine Homebuilding to prevent frost problems with a post an pier foundation. Although the bit in the magazine advised a slab of foam surrounding the tube a ways down in the backfill, and a crushed stone backfill. They also seem to be showing pieces of rebar inside the tubes, don't know if they come that way or one is supposed to add them. Obviously, we get to add a post holder while our concrete is still wet.
they've also got a .pdf file to help figure how many of the things you need.
http://www.foottube.com/index.htm
http://www.foottube.com/FootingTube_Cat04.pdf
Another interesting product is a fabric concrete form used for post and linear footings, and even for columns. Description here... http://www.fab-form.com/default.htm
It seems like it would be especially useful for pouring footings on uneven (is there any other kind??) bedrock.
Bart