Google Mobile app. Wow.
 

http://www.google.com/intl/en_us/mobile/apple/app.html
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/y3z7Tw1K17A&color1=0xb1b1b1&color2=0xcfcfcf&fs=1"> </param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/y3z7Tw1K17A&color1=0xb1b1b1&color2=0xcfcfcf&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

Stern just talked about this. The problem is that all too often it misunderstands what you say.

For most standard queries, it works darn well!

Automatic location aware searches are also killer.

I have few complaints . . . and it's free.