Talk origins has a useful FAQ about
Macorevolution. They trace the origin of the term to a russian entomologist named Iurii Filipchenko in the late 20s and its introduction to english to Theodosius Dobzhansky, one of the originators of the modern synthesis of mendelian genetics and darwinian evolutionary theory.
Traditionally in biology the distinction is between evolution below the level of species (micro) and evolution at or above the level of species (Macro). So by the traditional definition speciation is macroevolution.
Most critics of evolution seem to choose a different level for macroevolution for no readily apparent reason, and what that level is varies greatly, it often seems to be that macroevolution is always that level of change 'which has yet to be observed'.
TTFN,
WK