  The potential to discover a Standard-Model-like Higgs boson at the LHC in the
mass range from 150-180 GeV, decaying into a pair of W bosons with subsequent
leptonic decays, has been established during the last 10 years. Assuming that
such a signal will eventually be observed, the analysis described in this paper
investigates how accurate the signal cross section can be measured and how the
observable lepton pt spectra can be used to constrain the mass of the Higgs
boson. Combining the signal cross section with the analysis of the lepton pt
spectra and assuming the SM Higgs cross section is known with an accuracy of
+-5%, our study indicates that an integrated luminosity of about 10 fb-1 allows
to measure the mass of a SM Higgs boson with an accuracy between 2 and 2.5 GeV.
