New on the ProDevTips.com blog there's an article talking about the use of memcached on Dapper to increase the overall performance of the site.
Memcached is a very simple thing at heart; a daemon that runs in the background and that can be called from your code to store a value with the help of a key, and then retrieve said value with the help of the key used to store it; and it all happens in the RAM.
He talks briefly about the installation of the memcached server (on Ubuntu, in his case) via the source including a little trick he needed to do to get it to work correctly with the ld.so.conf file. He also includes the code for a simple class to implement it in your application.