Fondant (or sugarpaste as it is known in the UK)... decorators love it for the smooth porcelain finish and wonderful modelling capabilities. But when it comes to eating it... well that's another story!
There is at least one major manufacturer of cake decorating supplies which makes a truly in-edible version of sugarpaste. Unfortunately, a large number of decorators use it, not realizing that there are alternatives.
There are several manufacturers whick make some very tasty versions... my personal favourite is Mill Lane brand available at www.creativecutters.com in both the USA & Canada. I have also heard good things about Chocopan, which is based on white chocolate (but is a little pricey.)
If you want to make your own, there are several good recipes out there, there's one in Toba Garrette's book which I've used with good results. I don't find that the homemade versions are quite as workable as the commercial ones, but I may not have found the right one yet!
I would be remiss if I did not mention Marshmallow Fondant (MMF for short.) Similar to homemade in flavour and cost (which is substantially less than the commercial varieties) it is MUCH sweeter, due to having about 1/3 again as much sugar as scratch recipes. Many people believe it to be easier to make, but in reality, you only save one small step (mix gelatin into water...)
Most recipes I've seen list the glycerine as optional... I would not leave it out... that's what gives you the stretch to make it really workable... in fact I often double the required glycerine!
Whenever I work with rolled fondant, I always roll it approximately 1/4" thick... any thinner and it become much less forgiving! I also provide a substantial layer of buttercream underneath for those who don't wish to eat the sugarpaste