We won’t know if the Japanese probe Hayabusa actually brought asteroid materials back to Earth until spring 2011. Key quote from the project scientist:
Kawaguchi said his science team found “tens of particles” in Chamber A of the canister. The tiny particles are being removed one-by-one in an extraction process that is stretching longer than anticipated.
Note that they still have not opened Chamber B, which is thought to have had a better chance of capturing asteroid material because it was the chamber in contact with the asteroid Itokawa.