It's not too bad. It may not hurt to get a Haynes Manual for reference while you do it if you arent' familiar with how to remove the axle to replace the seal.
1994 Ford Mustang GT
1990 Ford Bronco II
2001 Lincoln LS V8
1970 Ford Bronco
2006 Harley-Davidson Sportster Custom
If you don't already own a Ford (or Ford owned product), get one.