usb ports

I am using an ibook G4 and am out of usb ports. Is there some kind of device that anyone knows of that you can plug into one of the ports and it branches it off to two ports?

I have only a modem(not in use)that was oem, and an oem ethernet pci card with nothing plugged into it,(pretty sure its not in use, as well)sharing band width with my raid controller.

I understand that # 8 if used, gives the best advantage, should I tinker?