Are unilaterally deaf people able to determine where sound comes from?
From what I could gather, there is a decent amount of variability in the ability to detect which direction sound is coming from in unilateral hearing impaired people. It would appear that some people have severely impaired localization skills, akin to someone with an earplug in one ear, but others can use their monaural hearing cues to better locate sound.

Monaural cues seem to be based on the structure of the outer ear as well as how the sound bounces off of the head and shoulders.

http://www.sciencedirect.com/science/article/pii/0378595594900531

http://en.wikipedia.org/wiki/Sound_localization#Monaural_cues