Yup. As of August 24th '06, Pluto officially isn't a planet, failing to meet the third condition of a planet's definition: "It must have cleared the neighborhood around its orbit. This means nothing of comparable mass may orbit near the planet. (While the phrase "comparable mass" sounds vague, there's no comparison between the eight planets and Pluto. The Earth is more than a million times as massive as any near-Earth asteroid. Pluto is only about 20 times as massive as Orcus, which has a similar orbit.)"
Not too big of a change, although it'll take some time to get used to not saying "Pluto" as you finish reciting the planets. Poor Pluto.
Makes you wonder, though, if there is alien life forms, if they're saying stuff like this about the earth. We're definately not a dwarf by any standard, but say someone lives on our moon (in this circumstance, the moon landing was shot in a studio, etc etc). Perhaps they think the earth is the sun or something. Or perhaps we're wrong. NASA just proved themselves wrong. Hm.