I used Fairy Godmothers, after reading about them in the Unofficial Guide and on All Ears website. We were very happy with their services. It's been over two years ago, but if I remember correctly they were bonded and insured. The company did background checks on the sitters, but I don't remember if CPR was mentioned anywhere.
One reason I went with Fairy Godmothers is because they seem to be mostly young grandmother types instead of just college girls. It was also fun to tell the kids that a Fairy Godmother was coming to play with them. And she brought her own toys.