Battery failing

Uhm, my 2 months old MBP's battery never was 100% to start with, it started out with ca. 98%, been decreasing ever since i started using it, but today it really got going down the hill...if i boot into leopard and do nothing, my estimated battery life is 1:45 hours, and it ain't misreading, cause in the afternoon it drained within one and a half hour! Is this covered under warranty? The machine is 2 months old