Wake-On-Lan (WOL) enabled computers can be sent special packets that allow for a change in power state. The first WOL machines could only be sent a "Magic Packet" that would instruct the computer to turn on when powered down. Though this is an older technology, this could still be useful in a variety of IT or home scenarios. FugueUp is a freeware application written just for this purpose. It sits in the systray and, after initial set up, you can power on a number of computers just by clicking the appropriate menu item. Written against the .Net 2.0 Framework, Unearthly Enterprises is releasing this simple (and hopefully) helpful application free of charge. Note: This utility only sends Magic Packets. It is up to the user to properly configure their computer with the proper hardware to be WOL enabled. To be helpful, there is a discussion in the included readme.pdf (in Appendix A) about how to do this but the actual system settings will vary from machine to machine.
Windows Server 2008