samarudge 16 Posting Whiz

Hi,
I currently run my website off one server (192.168.0.4) and all requests for port 80 (HTTP) are sent to this server. However I want 4 out of 10 requests to be proxied to my second server (192.168.0.3) but I don't want port 80 to map to server 2. I know about mod_proxy in apache but I didn't know how I could use this to split the requests between 2 servers.
I run Fedora 10 and am happy to install software other than Apache to do this.
Regards,
Sam Rudge