I've seen these around the internet and had to try it myself. My mom was cleaning out her fabric cupboard and had an extra piece of burlap so I snapped it up.
Cut it to the size you want. Sew on ribbon. Seriously, it was that easy.
A couple things:
1) sewing ribbon on was easier than I thought.
2) cutting burlap is more difficult than I thought. I used a rotary cutter but I think if I did it again I would use scissors and cut along the lines.
3) I left the edges raw but I would consider somehow hemming it.