Dave:
Get a copy of the 2006 Photographers Market. In it you will find the answers to your questions on sbmission requirements for different buyers, they vary. There is a good selection of digital cameras available from Canon, Nikon, and others. But don't be of the mindset that the camera is the end of the road, you need quality lenses. In addition, a great tripod, tripod head, sound technique, perfect composition, quality subject matter, and a host of other things. Yes, auto settings can produce professional quality images, but no matter what it is stll the light and you have to learn to read it and adjust for it. No camera digital or film will duplicate the range of the human eye. You must learn the limitations of your equipment.
Good Luck
Frank