I'd link to an article I wrote about website testing, but I used mod_rewrite to redirect every URL on my site to "Make a Bonfire of Your Reputations".

When I stop being so pissed off, you'll find my article at http://www.warplife.com/tips/webmaster/web-application-testi...

tl;dr: use a load generator. I wrote the article after some jackass woke me and my new bridge out of bed at three in the morning because his sun ultrasparc server fell over when brought live just in time for the christmas shopping season.