See the
Traffic Redirection chapter of the PF User's Guide.
Your redirection rule might be something like:
Code:
pass in on $internal proto tcp from any to any port 80 \
rdr-to 192.168.1.11 port 8080
Note that this will only redirect traffic based on TCP port number, not on underlying protocol; there is no inspection of TCP packet data payloads where the HTTP protocol is carried.