I have been looking for a simple tool to intercept and log HTTP conversations and stumbled upon Grinder.
Grinder is a pretty powerful load testing tool, but one of the things it comes with a simple port forwarder.
Here's how you use it, simply download Grinder, and update your CLASSPATH to include the grinder.jar provided in the lib folder.
java net.grinder.TCPProxy -remotehost example.com -remoteport 8082 -localport 8000 | tee /tmp/dump1
This will listen on localhost port 8000 and forward any requests it receives to example.com port 8082, while logging everything to /tmp/dump1 and stdout.