This article, by BYTE, is probably the quickest brief on BREW that I've seen. Check it out over at BYTE.com.
BREW makes cell phones interesting. Hold one in the air and it will listen to a song and figure out the title, album and band. If you have a diabetes problem, you can press a finger to the back of a cell phone battery to check stress levels with its biometric sensor. If you're a game player, you can tilt a camera phone about as the gamespace turns with the phone. All these phone applications are made possible by BREW.
You can ping this entry by using http://www.mamlambo.com/mt/mt-tb.cgi/547 .