Which seals? Axle or Pinion? The pinion seal sin't too hard, disconnect the drveshaft, mark the nut to pinion shaft relations (I use a center punch to mark them), remove the nut and the yoke, pry the seal out, tap the new one in, replace the nut and tourque to the spec in the manual. The marks should line back up if you did it right. Granted, the proper way to do it would be to replace the crush sleeve at the same time, and reset the preload, but it can be done without going that far for a simple seal replacement.
Axle seals get a little deeper, but are still within doing yourself. You will need to get a cover gasket, Permatex RTV Black will be ok as well. Pull the cover, remove the bolt holding the center pin (caution, sometimes they break just past the threads), pull the center pin. Then you push the axle shafts in to release the C lock, pull the axles out. The seals can then be pryed out and repaced, or if you want to do the bearings at the same time, use a 6' length of 1/2" metal conuit to knock the bearings/seals out from the opposite side. Assembly is the reverse.
