I was playing with Google's SMS feature. You can search yellow pages, residential listings, weather, movie times and definitions simply by entering some text and sending a text message to 46645.
It works really fast -- and well. It found my telephone white pages listing with all the correct info, told me the weather and gave me a definition for the word "parse".
Weather: Knoxville,TN 52F,Partly Cloudy Wind:NW 6mph Hum:54% Su:43-61F,Chance of Showers M:33-53F,Mostly Sunny Tu:39-53F,Mostly Sunny W:37-53F,Chance of Showers
The definition of parse:
* Parse: To divide a command or string of characters into its component parts. When you issue a command in Excel or Access, the command is parsed to see if all the va... Source: www.oznet.ksu.edu/edasi490/Glossary/cgw.htm
Granted, a more generic definition of parse (to analyze) might have been better.
There's been a lot of talk of sending headlines and info to users based on profile information they filled out, but I have never found that very useful.
Other than talking to other people, SEARCH via SMS seems like a killer app.
I used Google SMS via a Palm and a bluetooth enabled cell phone using FunSMS, which made it easy to do queries and get results (and save them).