PHP and load balancing

view story

http://serverfault.com – I have one major domain but the server spec behind it is not good enough. Hence I want to relay the traffic, in particular php-mysql queries to multiple smaller servers. How is that normally be done? (BTW I wonder how much traffic or number of php/mysql request a normal setup on ec2 micro instance can handle? ) I did have a look of EC2 load balancer. But is it only possible to load balance on machines of your own account? (HowTos)