There are 604K people in El Paso County (the county Colorado Springs resides within) as of 2009. About 400K live in incorporated Colorado Springs, though much of the east and north ends of the Springs are still unincorporated (they have country services), which would put the population to about 500K. The other 100K are Fountain, Monument, Manitou, Falcon, Woodmoor, and Black Forest, and some other small towns, which are far enough from Colorado Springs to be "outside" of it.
nice thing about the springs is that, despite the fairly large size (relatively, we ain't the big apple!), it still feels like a fairly small town, maybe 1/4 its actual size, as compared to say, Denver. It seems that violent crime in the springs, however, is more in line with the 400k population figure, unfortunately...