I'm managing large vbulletin forum, Apache 1.3 and PHP5 based.
The server at peak times hits load avg. up to 20-40 which makes it all slow and impossible to use.

* the database, MySQL v5 server runs on different dedicated server and seem to work great.

I would like to add one more apache server to split the load but cant figure how to do that.
When user logins to "www.server.com" I would like the system to automaticly decide which server should handle the request, without redirects to subdomains.

Like wikipedia for example, if you'll do "view source" on the web page at the bottom of the page you'll notice:
"<!-- Served by srv98 in 0.126 secs. --></body></html>"

I hope I explained it all clear

Thank you for your time and support.