Note: Before you fuck with your browser and come back here asking for help because it doesn't work, please don't. If you understand how the Mozilla preferences files work, how to reset them, how to fix them, then go ahead. But don't try this crap to get a 1 second jump on webpage loading unless you understand exactly what you are doing.
With that said, there is more than pipelining that can make your browser faster. It might not matter though if your network connection is fast enough. Granted, here where Syd likes to make everything as big as possible because he thinks that it increases his traffic rating with Alexa (it doesn't) you might see some benefit.
This is the best article that I have seen that shows you how to adjust the settings and sort them out. It has pictures and covers more than pipelining.
http://www.ubuntugeek.com/speed-up-firefox-web-browser.html