Hello and welcome to Just Answer. To track you want a scent hound such as a blood hound, fox hound, or beagle. (there are also other breeds of scent hounds). Scent hounds pick up many scents so you are going to need the scent of a deer and train the dog to that. If you go to a field dog /hunting/gun dog shop you can find different types of scents , however training it to find a wounded deer may not be possible , more likely it will find any deer within it's sense of smell, not necessarily a wounded one.
as for training you will need to get a couple of books or dvd's to show you how to train for scent and how to weed out other smells, such as human. I would check out all options as it pertains to picking a dog. On one hand if you get a puppy you can train them yourself, on the other hand someone may have a strong scent adult hound for sale and you will know what that dog can do.
This site offers both dvd and books.
amazon sells many books on training for scent http://www.amazon.com/Scenting-Wind-Scent-Work-Hunting/dp/0944875521
a store like Cabela's sells scents http://www.cabelas.com/catalog/ensemble.jsp?ensembleId=4346&rid=20&WT.srch=1&WT.tsrc=PPC&WT.mc_id=58000000000569336&WT.z_mc_id1=112200425