Ebay "Fuel Savers"?

[joevenzon]

* Coast. If you know that the next half-mile or more will be downhill, get up to speed, put it in neutral and turn your engine off. (Note that your power brakes and power steering will not work, don't do this in heavy traffic!) When you start back up, don't use the starter, put it in 4th or 5th gear and let the clutch out. When coasting with the engine on, leave the car in gear, most cars will cut the fuel, while in neutral it goes back to idle, which does not cut the fuel.

From what I've read, leaving the car in gear and coasting with the engine on uses very little fuel -- to me, the savings you get by turning the car off isn't worth it.

In general I just try to avoid braking as much as safely possible -- braking is wasted energy; instead anticipate stops well in advance and coast. Slow down quite a bit if the traffic light ahead is red... hopefully it'll turn green by the time you get there, and you won't have to dump energy into the brakes and then waste more energy accelerating again.