I apologize if this is a stupid question, but how can I edit "root" pages, such as http://MYIP/thepageiwanttoedit.php, instead of ones under my user directory (http://MYIP/~MYSHORTUSERNAME/pageidontwanttoedit.php) on MacOSX 10.5.8? Thanks!

sudo nano filename.php

Or, replace "nano" with "vi" or "vim" or whatever UNIX text editor of your choice.

You can also launch TextEdit the same way prefixed with the sudo command.