Interaural time difference, or ITD, is described as the difference between the times sound reaches both ears.
In other words, if sound emits from an equal distance, there is no difference in time; however, if the sound comes from the side, there will be a difference. Interaural level difference, or ILD, is the difference of the sound pressure level reaching both ears. There will be less intensity from high frequency sounds in the far ear.
Here's a video that shows a robot that can actually localize sound based on ITD and ILD.