This project allows you to control your X10 devices from any web browser.
The Arduino is used as a web server which puts up a page with controls for House Code, Unit Code, and Command.
(click on screenshot of Gort to see the page)
The response is sent back to the Arduino which sends out the X10 commands wirelessly through the CM17A module.
So far it's just on my local network but it appears to be working pretty well.
Still a few things I'd like to change, but the current Arduino source code is available here.