I just read the thread, and it posed interesting yet mixed comments... I have been backed up by an airline agent regarding baggage restrictions for domestic travel immediately following an international flight:

1. If you're on a connecting domestic flight after traveling on an international route, you will have no trouble at all. Best rule of thumb is to check-in ALL the way to your final domestic destination within the US at your first point of international departure. As is customary, you have to clear customs and drop off your bag again on the belt after clearing first port of US entry (Your luggage tag should have your bag checked in all the way to your final destination.)

2. The domestic coupon of your ticket also indicates how many pieces of luggage (now, the weight is rather confusing) you may check-in. If consistent with the limit imposed for the international segment, you will be just fine - no extra charges. However, airline agents can screw with you if they choose so to.

Anyway, in my situation, it's a bit more perplexing since I'll be traveling the domestic flight on a different date. My flight coupons are all printed under one ticket though.