How to user HaProxy?

http://itand.me/haproxy-nginx-php-architecture
http://37signals.com/svn/posts/1073-nuts-bolts-haproxy
http://www.alexwilliams.ca/blog/2009/08/10/using-haproxy-for-mysql-failover-and-redundancy/
http://www.howtoforge.com/setting-up-a-high-availability-load-balancer-with-haproxy-keepalived-on-debian-lenny