  We use the projected correlation function w_p(r_p) of a volume-limited
subsample of the Sloan Digital Sky Survey (SDSS) main galaxy redshift catalogue
to measure the halo occupation distribution (HOD) of the galaxies of the
sample. Simultaneously, we allow the cosmology to vary within cosmological
constraints imposed by cosmic microwave background experiments in a Lambda-CDM
model. We find that combining w_p(r_p) for this sample alone with the
observations by WMAP, ACBAR, CBI and VSA can provide one of the most precise
techniques available to measure cosmological parameters. For a minimal flat
six-parameter Lambda-CDM model with an HOD with three free parameters, we find
Omega_m=0.278^{+0.027}_{-0.027}, sigma_8=0.812^{+0.028}_{-0.027}, and
H_0=69.8^{+2.6}_{-2.6}km s^{-1} Mpc^{-1}; these errors are significantly
smaller than from CMB alone and similar to those obtained by combining CMB with
the large-scale galaxy power spectrum assuming scale-independent bias. The
corresponding HOD parameters describing the minimum halo mass and the
normalization and cut-off of the satellite mean occupation are
M_min=(3.03^{+0.36}_{-0.36})x 10^{12} h^{-1} M_sun, M_1 =
(4.58^{+0.60}_{-0.60})x 10^{13} h^{-1} M_sun, and kappa=4.44^{+0.51}_{-0.69}.
When more parameters are added to the HOD model, the error bars on the HOD
parameters increase because of degeneracies, but the error bars on the
cosmological parameters do not increase greatly. Similar modeling for other
galaxy samples could reduce the statistical errors on these results, while more
thorough investigations of the cosmology dependence of nonlinear halo bias and
halo mass functions are needed to eliminate remaining systematic uncertainties,
which may be comparable to statistical uncertainties.
