I just replaced mine and it was easier then i though. Just take the driveline off, take the flange off and then pry the seal out, pop the new seal in and then put the other stuff back on. Easy as cake.
WAIT! Before you put that flange back on, PLEASE make sure that you take some mild sand paper (maybe 400 grit) and rough-up the surface where the seal will touch. If you do not do this, then the seal will not break-in and it will leak again.
Regards,
BigMike