Is there a computer software to download and process my photos from any model of digital camera?

YES.. try adobe photo deluxe
or photoshop or image ready all from adobe...
also, windows does this for u just connect the camera and follow the windows wizard...
if ur question is , just connect any camera and have it process the photos, then , no u cant do this. windows has to recognize it first. then, u can use the programs mentioned above

If the camera has a memory card like CF or SD, it is convenient to have a USB card reader on the computer, so no downloading is involved.