Well getting it out is no problem. Here are the steps:
Remove tire
Remove brake caliper
Remove rotor
Undo the dif cover bolts
Make sure the oil pan is under the dif
Knock cover off, let oil drain out
Remove unit bearing (do not undo the spindle nut, just pull out the unit bearing and axle as one assembly)
Go to the other side and repeat these steps (minus draining the oil, duh)
Remove carrier bearing cap bolts
Remove carrier (it's probably in there pretty tight, this might take some persuasion)
Take a metal rod, put it down the axle tube with the bad seal, and knock the seal out.
Getting the new one in is a PITA. It's very hard to hit it in by yourself. I've found this to be the best method to put it in.
Get a socket that fits around the seal, but inside the outer lip of the body.
Place the seal in position and have a friend hold the socket and seal in place with one hand.
Next slide another metal rod or tube down the opposing axle tube and have the friend hold the rod on the socket.
Tap the seal in.
Put it all back together, making sure to correctly torque your bearing cap bolts, clean and put a new seal of rtv on the mating surface of the cover and dif, and torque your unit bearing bolts down tight as hell.