What's the difference between sugarpaste, gumpaste and fondant?

Sugarpaste and fondant are the same thing, just depends on where you come from. In England it is called Sugarpaste, in the US we call it fondant. Sugarpaste/Fondant is a sugar dough that is rolled out and used to cover a cake.

Gumpaste is a sugar dough that is made to dry hard and is used for decorations and 'edible' flowers.

OK, so I know how to make MMF. How do you make sugarpaste? And how do you make gumpaste?

Just as TexasSugar said, fondant and sugar paste are the same thing. MMF is a shortcut to homemade fondant. There are lots of recipes for making fondant, most include sugar, gelatin, corn syrup.

Gumpaste is also mostly sugar, but includes egg whites (or powdered egg whites) and GumTex or Tylose powder.

Nicholas Lodge has a website with a great recipe for gum paste. Although this is made of sugar, it dries very hard and is usually not eaten. Wilton has a mix for Gumpaste that is fairly easy to use, but isn't very white. The Tylose recipe produces a much more white paste.

Both fondant and Gumpaste can be purchased already made. Wilton's fondant is easy to use, but does not taste very good. Satin Ice or Pettinice tastes a lot better, but is more expensive.