Hi!
I work at a wildlife clinic twice a week and I love it. I highly recommend it as a supplement (not necessarily the core) of a pre-veterinary experience resume.
You should definitely check out if there are any state-sponsored wildlife rehabilitation centers in your area. I volunteer at one in my state. There are two volunteer veterinarians on staff so I get a teaching/mentoring element out of the deal too. I would recommend looking for one like this.
As for the work itself -- it's very diverse. We take in any wildlife (except aquatic mammals), treat their wounds, rehabilitate them, and eventually they are released. I do everything from cleaning out bins and washing dishes to feeding mealworms to baby birds every twenty minutes to treating wounds and splinting (so far with help) to administering IM, IV, and sub-Q injections. Because wildlife have no "owner", there is less liability associated with them.
Of course, it can be a little harder because no one is pulling for them if something goes wrong. There is no money for expensive treatments are surgeries... except in very special cases, animals that need these services are euthanized. On the other hand, encountering these problems has been another good experience for me and has helped me develop some of my own ideas about preservation of life and euthanasia. It's good to be exposed to these ideas before becoming a vet, so I value this element of the work as well.
Hope this helps -- good luck!
LeAnne
dreamdvm.blogspot.com