Just had a nightmare finding a binary for windows that wasn't cygwinized... eventually found it here
http://www.hackosis.com/wp-content/uploads/2007/12/nc111nt.zip
[update]
Jon Craton has mirrored this file in case the other link goes down
http://joncraton.org/files/nc111nt.zip
(Cheers :)
[update 2]
It seems that antivirus programs mark netcat as a threat when actually it is just a useful tool - see conversation and links in comments for details.