um, this link is to a site explaining pinion seal replacement. it sounds like one or both of your axle shaft seals are leaking. axle shaft seals on the front axle must be replaced from the inside. therefore its necessary to remove the carrier and ring gear assembly. its quite a big job for someone not experienced in this area.
At very least i would keep a eye on the amount of oil coming out and make sure to keep the oil at the proper level witch is the level of the fill plug.