I've been sharpening legitimately since January 2002 I've made a couple of hundred doing it on the side, mostly through word of mouth and fliers.
Almost everyone I talk to remembers the guy that used to come to their house when they were kids to sharpen their parents knives.
This nostalgia usually gets them thinking, and they always have a knife or two that need touching up, the problem is most of them have pretty cheap throw away knives that are way beyond the cost to value ratio needed to make sharpening their knives a profitable venture.
Now Retaurants, fabric stores, and hair dressers/beauty shops, that's where you can make some money, the key is to be able to sharpen their equipment in a short enough amount of time to make it profitable, this generally leaves out free hand bench stone sharpening, as this takes more time.
So now you have to get into jigs, and powered sharpeners, I've saved enough to purchace an EdgePro Apex, when I save enough I'll go for the Professional model. These are nice because you can literally carry them to the job.
My next step will be to put together a step van either with a converter to run 120 VAC equipment or convert motors to 12VDC at which point I'll probably get a Tormek and a grinder set up with the sharpening wheel and a leather buffing wheel, this to be capped off with a belt grinder.
Ultimately I would like to wind up with a rolling stock removal knife shop. One last recommendation set yourself up as a distributor for a decent brand of kitchen cutlery, so when you deal with people who have junk that they want sharpened you can at least offer them something that's quality made and worth keeping sharp, hell you might even make a few bucks selling knives.
One last bit of advice if you do this on the up and up, you'll be able to write off your equipment on the following years taxes, it does take time but in the end I believe it'll be worth it. I'm not gonna get rich doing this, but I like it, and every year I'll make a little more, and this sure helps supplement my knife collecting habit.
