I have played around with Pound a little bit. It is a reverse proxy and load balancer in one, and it can be used as only a reverse proxy if you like. It is very simple to configure as either, and Pound even senses if one of the systems is down and stops sending requests to the dead server.
It supports SSL (but passes the request to the destination server unencrypted) and even the Apache log format. Pound is very simple, fast and stable which is also secure because it does not require root privileges to run.
Pound is simple, yet extremely powerful and versatile and is better than running a full blown Apache instance especially if you just need the Proxy features.