I do the same as shellyp. I machine stitch the binding to the front, then on my ironing board I fold it over to the back, then secure it to the quilt using Wundaweb (iron on hemming web/fusible web/ not sure what you call it in the US). I found this better than pinning as I got a straighter line, held it down well and made sure it was covering the stitching that I had done from the front. Then you go back to the machine and stitch in the ditch from the front.
I am no expert either, and I'm sure some of the others on here will tell you more on the reasons, but I think hand stitching the binding on the back is the more 'traditional' way of doing it, so that you don't see the stitching on the binding on the back. When I have been to quilt shows they are all done like this.