  We study the luminosity and color dependence of the galaxy 2-point
correlation function in the Sloan Digital Sky Survey, starting from a sample of
200,000 galaxies over 2500 deg^2. We concentrate on the projected correlation
function w(r_p), which is directly related to the real space \xi(r). The
amplitude of w(r_p) grows continuously with luminosity, rising more steeply
above the characteristic luminosity L_*. Redder galaxies exhibit a higher
amplitude and steeper correlation function at all luminosities. The correlation
amplitude of blue galaxies increases continuously with luminosity, but the
luminosity dependence for red galaxies is less regular, with bright red
galaxies more strongly clustered at large scales and faint red galaxies more
strongly clustered at small scales. We interpret these results using halo
occupation distribution (HOD) models assuming concordance cosmological
parameters. For most samples, an HOD model with two adjustable parameters fits
the w(r_p) data better than a power-law, explaining inflections at r_p ~ 1-3
Mpc/h as the transition between the 1-halo and 2-halo regimes of \xi(r). The
implied minimum mass for a halo hosting a central galaxy above a luminosity
threshold L grows as M_min ~ L at low luminosities and more steeply above L_*.
The mass at which an average halo has one satellite galaxy brighter than L is
M_1 ~ 23 M_min(L). These results imply a conditional luminosity function (at
fixed halo mass) in which central galaxies lie far above a Schechter function
extrapolation of the satellite population. HOD models nicely explain the joint
luminosity-color dependence of w(r_p) in terms of the color fractions of
central and satellite populations as a function of halo mass. The inferred HOD
properties are in good qualitative agreement with theoretical predictions.
