Simple patch that allow port redirection with any destination address.
Example:
ipfw nat 3000 config log redirect_port tcp localhost:3000 80
ipfw add 65500 nat 3000 ip from me to any src-port 3000
ipfw add 65501 nat 3000 ip from any to any recv ${IFACE_INTERNAL}* dst-port 80
Full example:
imslu