A search for new particles (X) that decay to electron or muon pairs has been performed using - approximately 200 pb-1 of pp-collision data at ps = 1:96 TeV collected by the CDF II experiment at the Fermilab Tevatron. Limits on σ(pp- ! X)BR(X ! '') are presented as a function of dilepton invariant mass m''> 150 GeV=c2, for different spin hypotheses (0, 1, or 2). The limits are approximately 25 fb for m''> 600 GeV=c2. Lower mass bounds for X from representative models beyond the standard model including heavy neutral gauge bosons are presented.