Simplest safety tip of all:
Extinguish the fire while you put in the bird and relight once it's in.
That way if there is an overflow, there isn't a resulting huge fire.
Yes, follow the safety tips mentioned above!
All in all, it's a pretty expensive way to cook with the price of peanut oil. It's really messy to strain and store in a cool place.
The two tips already posted about determining the oil level and turning off the fire when putting the bird in are key.
I've done 5-6 deep fried turkeys with my brothers, and have always had great success. Don't get too big of a bird too; we stick to the 12-14lb range for our fryer.
Another thing we do is mix up some stuffing that would normally go in the turkey if roasting it; but add a couple eggs to the mix to hold it together, form in to balls and deep fry as well.