Re:wordpress, again? (Score 4, Informative)

Some of that is Wordpress' fault for not having an easy way to run mass upgrades. My employer has 15 different sites running on Wordpress and the fact that I have to log in to each one manually after upgrading the files and click a link to handle the database update is annoying.

This drove me nuts at my current job for about 2 months - you need Wordpress Network.

There's the easy way and the hard(er) way to do this:

This is the official easy way, but it's never worked for me (last tried in Spring of 2011). The nice thing is that it's all stuff built into WordPress, so you should be able to do it without any problems. I'd say it's probably worth giving this a try with one site, and if it works, run with it.

This is more down and dirty way that will definitely work, and is more or less how I did it. A little SQL editing never hurt anyone.
Also, this is a great companion to the bavatuesdays link. He goes on about his DNS in the first few paragraphs, but the second half of that post has some good details about where files need to be, and how links and such need to be updated.

Once you have a network, you a fantastic "Update Network" button. Boom. Take the rest of the day off.