Juan,
Thanks so much for providing the links and screen capture. I read the gis help on the links and now understand that the legend property columns just breaks up an specific legend item intom multiple columns; it does not lay all of the legend items out horizonatlly, like I need to. However, your help gave me an idea: I could make insert a bunch of legends into my mxd, each with just 2-3 items, I could arrange these legends together, stacked, on top of a white graphic background, and delete the word legend from all but one. Thus, I can quickly create a "horizontal" legend. Check out the attached screen capture.
I appreciate you inspiring me to come up with a work around,
Ken