Stop email harvesting - Windows 2003 server

Anyone know a good spam buster to stop email harvesting for a Windows 2003 server platform.
I have used Master Spambot Buster on Linux before to good effect - anyone know if this can be used on Windows 2k3?

To chmod 755 on windows, is it just a case of setting "read / execute" permissions on the internet guest user?

Thanks in advance

Check this out,

http://www.wbwip.com/wbw/emailencoder.html

http://automaticlabs.com/products/enkoderform/

This one is industrial strength encoding

Very nice!