so you want to connect two hard drives to what? the same ide connector? or the same computer?
you can have up to four devies, let it be hard drives or cd-roms in one computer, just connect the sceond connecter on your ide cable, that flat ribbon type cable you have conected to you hard drive already, and it shouldwork fine, but make sure that you set the jumper settings on the hard drive as slave.
if you do not know what the settings are, they should be marked on the drive itself.
hope that helps