Wordpress "Briefly unavailable for scheduled maintenance" Fix

Personally, I have never seen this error before Wordpress version 3.0.3. When a new version of Wordpress is available for download, a site stripe will show up in your site's admin area for an automatic Wordpress update. Click it, and it will go through the motions of updating your site:

Don't worry, this one is really easy to fix. It's really just an annoyance. Go to your FTP space for the Wordpress site in question, and look for a file called ".maintenance" - select it and delete it. That's it, you've fixed the problem :)

Why does this problem occur in the first place? It is most likely a permissions issue with one of your Wordpress folders, most specifically something in "wp-content/upgrade" - try setting that folder and its subfolders to CHMOD 777 before doing any kind of update.

If this doesn't work, then read my "Could not create directory fix" tutorial. If THAT doesnt work (highly unlikely), then it's something you may want to ask about on the Wordpress troubleshooting forums.