Here's netcat 1.11 compiled for both 32 and 64-bit Windows (but note that 64-bit version hasn't been tested much - use at your own risk).

I'm providing it here because I never seem to be able to find a working netcat download when I need it. Hopefully, the monkeys at AV companies won't add this to dangerous downloads lists anytime soon, like they do with other downloads I'm able to find.

Small update: netcat 1.12 - adds -c command-line option to send CRLF line endings instead of just CR (eg. to talk to Exchange SMTP)