This article is from the sci.fractals FAQ, by Michael C. Taylor and Jean-Pierre Louvet with numerous contributions by others.
Noel Giffin gets good results with the following setup: Use 100
ISO (ASA) Kodak Gold for prints or 64 ISO (ASA) for slides. Use a long
lens (100mm) to flatten out the field of view and minimize screen
curvature. Use f/4 stop. Shutter speed must be longer than frame rate
to get a complete image; 1/4 seconds works well. Use a tripod and
cable release or timer to get a stable picture. The room should be
completely blackened, with no light, to prevent glare and to prevent
the monitor from showing up in the picture.
You can also obtain high quality images by sending your Targa or GIF
images to a commercial graphics imaging shop. They can provide much
higher resolution images. Prices are about $10 for a 35mm slide or
negative and about $50 for a high quality 4x5 negative.