We report atmospheric parameter estimates (Teff, log g, [Fe/H]) and other information (radial velocities, proper motions, distance estimates) for roughly 40,000 stars (out of a total of some 75,000) from the third public release of the Sloan Digital Sky Survey (SDSS), DR-3. As part of this exercise, we have compiled a set of spectral templates that might prove useful as examples of the kinds of stars that will be found in the SEGUE (Sloan Extension for Galactic Understanding and Evolution) project, which is part of the proposed SDSS-II extension. This work received partial funding support from grant PHY 02-16783, Physics Frontier Centers/JINA: Joint Institute for Nuclear Astrophysics, awarded by the US National Science Foundation. C.R. acknowldeges support from NASA grant HST-HF-01143.01-A.