Load balancing for web servers

[Baldur Gislason]

I'd like to set up a load balancing and resiliance system to
load balance between a bunch of web servers running Apache tomcat (slow java stuff).
Ideally I'd like each client IP to get mapped to a certain server and keep that
mapping throughout the entire session. I'd also like to have some means of detecting
a server that goes down and yank it from the load balancing pool. I do understand I
may have to write some code on that side.
Any suggestions to an approach? Can Netgraph do something like this?

Baldur