molex connector = the connector that supplies power to your standard IDE hard drives. These are a great source for tapping power if you want something only on when the PC is on. The 4 wires supply +12v, +5v, and two grounds (yellow, red, black, black). These only receive power when the PC is turned on. So - you connect the power and ground cables from your USB cable that leads back to your device/hub (it has 4 wires, the other 2 are for data) and splice these into the red and black wires on the molex connector.
perhaps wording was poor..i mean to say tapping the wires that lead to the molex connector (although getting a male/female pairing on the connector itself is also possible).
good info at:
http://www.playtool.com/pages/psucon...tml#peripheral