Software

Girder - Windows based software that controls lights (X10, Insteon), media (iTunes, MCE), security systems (ElkM1) and applications running on the PC.
http://www.promixis.com

CQC - Distributed automation system controlling lights, security and media.
http://www.charmedquark.com/

mControl - Windows Media Center based home automation software. Supporting a wide variety of hardware.
http://www.embeddedautomation.com/EAHAmControl.htm

LinuxMCE - Linux Based home automation software. Managing media, lighting, security and voip systems.
http://linuxmce.com/

HomeSeer Technologies - Offers central control of lights, appliances and security systems from your PC.
http://www.homeseer.com/

Macintosh Home Automation - Macintosh software for 2-way X10 home automation and security
http://www.shed.com

InHome Solutions - Provides automation and surveillance solutions for homes and businesses.
http://www.inhomesolutions.com/

Home Automated Living - Voice recognition software for Windows 95/98 that supports HVAC, telephony, infrared, Internet, X-10, and security.
http://www.automatedliving.com/

EventGhost - Open source home automation application for Windows with support for X10.
http://www.eventghost.org

Scott Crevier's Home Automation - Offers an X-10 Web Interface and X-10 Win95 QuikMenu techniques.
http://www.x10.crevier.org/

The Java X10 Project - Java APIs and Forum for managing an X10 hardware network.
http://x10.homelinux.org

ECS automation software - A general-purpose Windows/Linux automation program that is suitable for virtually any tasks.
http://OmnipotenceSoftware.com

Heyu X-10 Linux Home page - Gadget lover's page, featuring a program (heyu) to operate the X10 CM11a interface from a Linux system.
http://heyu.tanj.com/heyu/index.html