How to color balance imagery

I intend to do more with this in coming months, but for now have a look at these posts:

1)  Color Correcting a Mosaic Dataset from ArcGIS Resources Online for v. 10.1

2) Tips for Color Balancing a Mosaic Dataset

3) Color balancing GeoEye Imagery.  This particular blog post is specific to GeoEye satellite imagery but contains several useful steps that are generic.