Ah... sorry to double post (too late to edit). But to correct myself, the terms 'microevolution' and 'macroevolution' weren't coined by creationists.

The scientific definition of macroevolution is: "...any evolutionary change at or above the level of species."

The scientific definition of microevolution is: "...any evolutionary change below the level of species, and refers to changes in the frequency within a population or a species of its alleles (alternative genes) and their effects on the form, or phenotype, of organisms that make up that population or species. It can also apply to changes within species that are not genetic."

(source: http://www.talkorigins.org/faqs/macroevolution.html)

Creationists often assert that "macroevolution" is not proven, even if "microevolution" is, and by this they seem to mean that whatever evolution is observed is microevolution, but the rest is macroevolution.