Some of the newer mobos that support ACPI and STR have it built right in. I recently built a new box using an Epox ep-8khm, intel 10/100 nic, and a matrox g-400 vidcard. It actually works- when the system goes to sleep, everything turns off, even the psu fan. The 5vsb from the psu keeps the program running in memory and the power led blinks. Tap the power button and everything comes back up. I've built several systems that were supposed to do this but never would, so I'm extremely pleased with my little epox for this and a variety of other reasons.