Sorry posted before checking spelling in subject.
When I booked our flights with United for next season I was told that there TWO suitcases, 50 lbs each, are allowed because it is an International flight. I checked their web site and YES it does state that.

According to their sites=
United = Yes
Delta = Yes
AA = Yes
USAir = NO

"El Muchacho De Eagle Beach"
Eagle Beach Boy
Ontario, Canada