If you have an old CD-ROM cable that is used to connect the audio pins of the CD-ROM drive to the soundcard you can use that. If you have an old computer case, you can cut loose one of the motherboard connectors (like Reset, Power, H.D.D., LED) and use that.
The spacing of the pins on that header is the same as the pin spacing on a Hard Drive, Motherboard pin header, etc., so any connector that will fit on those can be modified to work on the Ipac header.
If you don't have any of those available then just connect them to the PC power supply. The red wire is 5v and the black wire closest to it is ground.