Prot# 189-00: Rndmzd, Dbl-Bld, Dbl-Dummy, Prl'l-Grp, Mltcntr Study to Evaluate & Compare Effects of Alendronate & Raloxifene on Bone Mineral Density in Postmenopausal Women w/ Osteoporosis (EFFECT Study - Efficacy of Fosamax® vs Evista® Comparison Trial)