  The WMAP satellite has completed 3 years of observations of the cosmic
microwave background radiation. The 3-year data products include several sets
of full sky maps of the Stokes I, Q and U parameters in 5 frequency bands,
spanning 23 to 94 GHz, and supporting items, such as beam window functions and
noise covariance matrices. The processing used to produce the current sky maps
and supporting products represents a significant advancement over the first
year analysis, and is described herein. Improvements to the pointing
reconstruction, radiometer gain modeling, window function determination and
radiometer spectral noise parametrization are presented. A detailed description
of the updated data processing that produces maximum likelihood sky map
estimates is presented, along with the methods used to produce reduced
resolution maps and corresponding noise covariance matrices. Finally two
methods used to evaluate the noise of the full resolution sky maps are
presented along with several representative year-to-year null tests,
demonstrating that sky maps produced from data from different observational
epochs are consistent.
