You can run them through Photoshop or a similar image manipulation program and edit the color settings to black and white. How you do that exactly depends on the program. I have GIMP, and in that program it's under "Image", then "Mode". It might be different in whatever program you have.
If you don't have a manipulation program, you can download GIMP for free (http://www.gimp.org
The other method is to change your camera's color settings to black and white. That would probably be the easiest way.
at 8:06 AM on May. 25, 2011