A single IDE channel can utilize two devices. You can make the hard drive the master and the dvd a slave.
Why even bother with the IDE? All new mobo's have SATA ports. Unless you need that old hardware, I'd replace it with newer SATA devices, at least the hard drive as it will be much faster.
ESPECIALLY for the hard drive. If you have an old IDE CD or DVD that you want to keep, it's not as big of a deal (for a single device there should be jumper settings either on a lable on the device, or google it). But the SATA HDs are way faster than IDE.