Yes, you can buy a splitter that has two ends on the one side. Generally there is more then one Audio plug on a motherboard, commonly labeled CD and AUX. There may also be a smaller white plug on the motherboard that matches some ends on the CD audio cables.
Now that said, that cable is only used with analog audio. If you use digital input you don't need that cable at all. If you have XP then it should work without any settings. In Windows 9X you can set the audio to digital in Multimedia settings in the Control Panel or in CD-ROM properties in Device Manager. There's also a Digital Input option in most players like Windows Media Player.