1. Network load balance, that's the job for 3rd or 4th layer switch, or some router can do these, and ATM switch always has this function.
2.Local DNS load balance, that's cheap way, but not so good performance. and better take the DNS server into a cluster or HA system. and for intranet DHCP's load balance also are considerable. and in some huge network and web system, even DNS-self also be balanced. this is mainly part of web system load balance.
3.storage load balance, such as Andrew File Sytem(AFS)--it's very like NFS. and Cache file load balance. it's very important part for web system performmance.
websphere performance pack is a excellent solution, it's called IBM network e-dispatch in previous, and now called websphere edge sever.