The first year results from WMAP, based on temperature anisotropies of the 
Cosmic Microwave Background, determined several features of our universe 
which had been known only roughly; its age is 13.7 billion years; 
73% of the energy density is dark energy; space is nearly flat.
With three years of data we now have much smaller uncertainties and
useful measurements of microwave polarization which is the key to our
ability to constrain cosmological models precisely.  I will review the
experiment and show that our results are consistent with a broad range
of astronomical and nuclear abundance data.  The simplest model of 
structure formation, the Harrison-Zeldovich model, predicts a flat initial 
power spectrum, which is to say equal variance on all scales, while 
inflation predicts a small departure from a flat spectrum. The WMAP data, 
for the first time, provide a measurement precise enough to show a
preference for inflation instead of a flat spectrum.  This eagerly
anticipated test is the `smoking gun' of inflation.