I retouch photos for others, and am just sorting my website now. Brian and the others have some really good points, particularly re what I call the "rote editing" - the bulk stuff which photographers can pay next to nothing for elsewhere (I personally don't do this sort of editing, and I charge in 5 minute blocks for the "tricky edits" and retouching that I do). If he goes ahead with it, I wouldn't be expecting an income of any significance for a couple of years absolute minimum. But it depends what you want to achieve and how many hours you are prepared to spend sitting on your behind, and for what amount of money.