It sure sounds like the flame sensor to me.
what you can do is
make sure the power to the furnace is off and just check and see if the sensor is covered with soot. often, a cleaning with a emery cloth or crumpled up tin foil will be enough to get it working again.
http://homerepair.about.com/od/heati...ectr_ign_9.htm
But yes, Keith is a good man to help you.