PSX games do not come as ROM's, they are technically images. A ROM is the copy of the memory from a Read-Only Chip as found in cartridges of yore. It's distinctly smaller in size than data from a CD. A CD Image (which is what you'll want) is a record of the data on a CD transfered into a medium which is easier for a computer to process directly. Many people who emulate CD's (myself included) prefer to create an image of the CD and run that rather than running straight from the CD, since it's faster for the computer to process. The standard for these types of files are usually ISO's, though there are several in circulation, such as .NRG, .IMG., .BIN depending on the data system used.
However for legal reasons I can't possible tell you where to go to find these articles, and strictly speaking you shouldn't be asking here either.
