The moon's orbit is also growing at about 4 cm per year. This is because of more wacky effects of gravity. The moon pulls Earth's oceans slightly away from it, creating the tides. But because the resulting tidal bulges are closer to the moon than the center of earth, the gravitational force is therefore stronger. The tidal forces create friction between the Earth and it's oceans, causing Earth to slow down slightly and it's oceans to end up somewhat ahead in their rotation. This in turn causes the moon to be affected by the gravitational force of the tidal bulges, pulling it forward in it's orbit (since the Earth and its tides spin faster than the moon orbits around them - it's like the tidal bulge is tugging the moon behind it as it rotates). The growing distance has been proven to be true because astromers can bounce lasers and shit off of reflectors on the moon left there during the Apollo missions and judge the distance from that.
Apparently all of that means that Earth's days are growing slightly longer over time as well. The actual measurement escapes me.
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