We use this
http://www.perfect-prescription.com/dentalhygiene.htm. It comes in little soap flakes that you place on your teeth and brush and it foams up nicely. No glycerine or flouride! The taste is pretty mild, it comes in peppermint, spearmint, and cinnamon, but I don't think those flavors come out much. It does taste a bit like soap, but not bad at all. We bought the package that comes with the book, which is an interesting read, but nothing that you can't find on the internet. I can even get my 7-year-old to use it and she's VERY picky about taste~