[It's Just Eric]

+1 on svxcess. Dont know about the ding remover dealies...all I can think of is another redundant Billy Mays yelling at me commercial....
HEY, BILLY MAYS HERE WITH THIS AWESOME NEW CAR DNT REMOVER!!iNTRODUCING THE NEWLY REDESIGNED DING KING!!.....
Best way would probly be to take the door off, remove the lower body cladding, tap off mabey a half inch around the entire door, and use good ole paint stripper on the mess. Clean up the surface and edges with some 220grit on a da (Random orbital sander) and roguh up the dinged areas with some 60. Smooth the whole thing over with some body filler. youll need to apply more than one layer, of course.you should sand the body filler first with 60, then 120, then 220 to finish it off. Run your hand down the panel repeatedly and feel for ANY dents, dings, or high spots. If you can feel it, you'll see it when its painted.Youll want to focus some attention at this point to the lower molding thing you pulled off. Run the da over that with some 400 grit and feather out any chips or scratches. To do this without making a butthole of it, hold the da nice and flat, and dont hold it in one place.Look to sand the area untill the edge of the chip or scratch is no longer visible. Once again, run your hand along it repeatedly and feel for any low spots (Creaed by you digging with the da) or edges. next bomb on some primer. Start off with two or three coats on the bodywork itself, then give the entire panel a a coat or two for good measure.On the lower panel thingy youl want to put a layer on wherever you broke through the paint down to plastic. Dust on some spray paint to use as a guide coat for wet sanding. Wet sand the door with a block and some 400 grit. Make sure you have every bit of the primer's orange peel removed. The panel should have NO guide coat on it whatsoever, and if you did it right, it should be the smoothest thing you've felt on an automobile
Now you gotta scuff your fender and rear quarter for a blend. The best and most drivewayable solution is to wet sand the panels with 1500 grit sandpaper and a block (Be it hard or soft) untill the clear coat's peel patern is gone (By the way...if you want any paint job to look good...do this to it and then buff it...at your own disgression of course)
now all you have to do is hang the door and drive it to your local body shop. all they have to do is tape it and shoot it, clear coat the door, fender, and rear quarter, and viola! your door doesnt suck anymore (Unless your bodywork wasnt good...then it probly looks worse right now)

....Or pay someone to do it for you, probly the safer bet if you know a good place.