The hub is an AU9254.
From the alcor website: "
AU9254 is an integrated single chip USB hub controller designed for the emerging industry-standard Universal Serial Bus (USB). The AU9254 supports four USB downstream ports. Each downstream port has power switch control, and over-current sensing. "
datasheetarchive
The fact that each port has power switch control is impressive, and even might come in handy :-).
Port 1 is on the right side to the front
Port 2 is on the right side to the back
Port 3 is internally connected to the chesen PS/2 converter
Port 4 is internally available as solderislands on the right back of the motherboard, near the clamshell hinge.
Right under the 8 of R538 the output of iwifi is available. The internal wifi was probably meant as an USB device with a small internal connector.
Power on ~3.3v, and off is 0v. You'd probably need to add a transistor and a fet.
"under the 8" means that you first have to turn the board until R538 is horizontal ;-).