I did try it once using one of those flint scrapers, you know the flint sticks you can buy, I wasnt very succesfull but will be trying more pretty
soon.
Strike master make one here
strike master
or for the uk, about halfway down the page.
Flint Spark
or if you want to think completely outside the box
try these
or this
The commando saw is pretty nifty aswell.
[edit on 18-5-2008 by Dar Kuma]