what's the best way to season a new cast-iron skillet?

I read in a recent Cook's Illustrated that flaxseed oil is the best fat to use for seasoning-I tried this on one of my pans, and I think they're right.

if my pans ever need touch-up seasoning, i make fried chicken-- or at least that's my excuse for making fried chicken.

A bit late on this, but I recently helped our friends over at the Hairpin with this same question! You can find (the very lengthy) answer here:
http://thehairpin.com/2011/08/ask-a-clean-person-butt-marker-cast-iron-and-hood-grease

Boulangere, I just drove back home with some leaf lard so, as a seasoning, I would answer mighty fine.Which means I have to make some pastry dough this week. I'm not a big fan of manteca because I think it smells kind of funky.

yes, sbk, I've found the same stickiness with non-animal fats for seasoning.

I prefer to use solid fats for seasoning - lard, bacon, shortening and not oil. I have found oil can leave the pan feeling sticky, and not developing that lovely patina. So solid fat in pan in oven at 300 or so. Make sure you swirl it once the fat has melted so it coats the whole surface.

thirschfeld and pierino, because someone is bound to ask, how do you think lard would work as a seasoning?

Heat your oven to 350 degrees. Coat the interior of the pan with shortening or vegetable oil. Heat the pan in the oven and them wipe out the excess oil. Let the pan bake for 3 to 4 hours. It won't burn but it will have a strong smell so you may want to open a window. You will know the pan is done when it is cool it will look like it has a thick coat of shellac on it.

Most brands such as Lodge come preseaoned now, however the best way is still to fry up several batches of bacon in it and then rub it clean with towels. Don't scour it and never stick it in the dishwasher. With each meal the seasoning will improve. You do have to scrub, but never use a Brillo pad on it.