Shouldn't be too hard. I've changed them out of RE contol arms plenty of times. The ones in the axle casting might be a little tougher.
I usually get a torch and heat up the metal sleeve in the center, then it usually just shoots out of the rubber really fast. It's kind of funny... Anyways, do that and then pry the burning rubber out of the outer sleeve. Then either pry the outer sleeve out, or if it wont budge cut it out with a sawzall or something.
Then BFH the new one in, and hope it goes in all the way, because you can't really set your axle housing up in a press...