TutorialCachingStory - memcached - This is a story of Caching
One day the Sysadmin realizes that their database is sick! It's spewing bile and red stuff all over! Sysadmin declares it has a fever, a load average of 20! Programmer asks Sysadmin, "well, what can we do?" Sysadmin says, "I heard about this great thing called memcached. It really helped livejournal!" "Okay, let's try it!" says the Programmer.
more on code.google.com
The best introduction to memcached I've seen (not that I've seen many).
