ATACs are fancy shmancy mt bike pedals, made by Time and in your choice of carbon fiber, aluminum, or cro- moly. And colors! They have 15 degrees of float, as opposed to the 5 to 7 you get with the average mt bike pedal. Speedplays can release a little too easily for dirt work, and ATAC have the big float some of us like. Really high quality trick pedal, designed to shed mud and take a beating. I like mine, but they are not a beginners pedal.
They can be really tricky to release, the best technique I've found is to snap the foot sideways while still spinning- which is good dirt form anyway.
Time makes awesome road pedals too, and if anybody gets too fed up with LOOK it could be something to check out. The systems are not at all compatible, you'll need adapter plates for non Time road shoes, but some very serious racers use 'em and love 'em. My LBS guys rave about them, though I've never used them or even had a good look at them.
You can also always put mt pedals on the road bike for touring. There's a lot of that done, and you can keep the road shoes if you like the super stiffness. a lot of them are easier to deal with than road pedals.

missliz