Keeping your Wordpress alive during a traffic storm
Turbocharged -- a for-pay solution to the problem -- offers a solid tutorial on how to weather a traffic storm. It's filled with good advice about Apache settings and MySql but, ultimately it's a sales pitch for their software. Unless you're blogging professionally, you're probably not interested in paying a license fee to decrease page generation times and increase the number of clients you can handle through caching. Fear not, there are cheaper (as in free) solutions.
If you follow the tips in Turbocharged's tutorial to tune up your blog's server settings, and replace Turbocharged with WP-Cache -- a free solution to Wordpress' CPU intensive page generation -- your wallet will be no lighter but you'll have increased the number of simultaneous hits your blog can take by ten to twenty fold.