Alright, well here is a post I'll copy from autopia explaining how I did it. Definitely let me know if you have any questions.
"Sure. So initially I figured it would just be a chip repair, but bigger. I didn't anticipate that the repaint was so thick (you can see in the before, it's like 2mm thick), so I had to run out and get some automotive putty. (3M super red putty). I sanded the crud out of the area around the chip to kind of flake off everything that wasn't totally sticking to the plastic bumper cover then cleaned it and filled it with putty and leveled that with a plastic trowel deal (for repairing drywall in corners), let that dry (it on;y took like 30 min), then I made a template with a peice of paper and cut that into some tape then taped it off as close as I could, then I used Duplicolor black for bumpers (I guess it has a flex agent in it), and just sprayed 2 coats, then a cc coat, then sanded again, polished and that was it.
It came out ~90% as good as new I'd say, my sis was pretty psyched. I have three minor issues with it personally - first there is a small shallow area in the center where the putty kind of sank down as it dried, second my tape template wasn't perfect so there is about 3-4cm of area in between and around the chip that got paint, so they look good but don't match the rest of the bumper totally. I think over time that will fade though. Last there is more OP in the repair than around it, but that was sort of a given. Anyway, you can't see it from more than a couple feet away, so I'll live with it.
"
Here is the thread:
http://autopia.org/forum/showthread.php?t=69958
Next time I do something like that I am going to be more careful with my template so as not to cover any areas outside the chip. I'll also use some paint thinner to thin the paint out so it runs a little less (which is why i got some of the orange peel). Otherwise it came out pretty decent. I guess the tricky part is actually spraying, so maybe I'll write something about that later this week or something.