Load balancing with linux

Hi all,

I have to deply a structure with a Linux Server act as load balancer.
I've found many load balancer projects on SourceForge but mybe someone can
suggest me.

I've to use it only for web load balancing. But I'm also in doubt if use
two servers in cluster configuratio for load balancer.

Backend should have 4 servers with apache2+php. A mysql server will be
available only in backend network.

What about ultramonkey? Any impressions?

Thanks
Stefano