http://www.securityfocus.com/archive/1/330004/2003-07-20/2003-07-26/0

Proof of concept:
http://lasecpc13.epfl.ch/ntcrack/

Paper:
http://lasecwww.epfl.ch/pub/lasec/doc/Oech03.pdf

Swiss researchers released a paper on Tuesday outlining a way to speed the cracking of alphanumeric Windows passwords, reducing the time to break such codes to an average of 13.6 seconds from 1 minute 41 seconds.
http://news.com.com/2100-1009_3-5053063.html?tag=fd_top