So I learned something valuable recently.. it's basically how to make small text readable in Flash movies:

The box on the bottom shows text from a Flash movie with the text set at 11 point with the font set to Arial. The box on the top shows the same text with the font set to _sans and Use Device Fonts checked.

The net effect of this is the text is aliased rather than anti-aliased. It also can significantly reduce the size of the SWF file because the information for the font doesn't have to be embedded in the SWF. Using the device font's can also help you if you are trying to get unicode characters to show up.. but it can be limiting because you are limited to the fonts installed on the users system.