I found this list of urban areas in the US: http://proximityone.com/urbanpopulation.htm

It says that the urban area of OKC, in 2009, was 322.4 sq. mi. and had a population of 807,224; the density was 2,504.2 people/sq. mi.
Norman's urban area was 30.2 sq. mi. and had a population of 94,867; the density was 3,137.3 people/sq. mi.

However, as of the US Census 2010, the definition of "urban area" will be different, and is still pending I believe.

If the new definition is approved, it will combine OKC and Norman and become known as an "urban agglomeration."
http://proximityone.com/urbanagglomerations.htm

Using this new definition for the 2009 stats, Oklahoma City-Norman would have had at least 902,000 people within around 352.6 sq. mi., with a pop. density of 2,558 people/sq. mi.