I posted this question on the Apple Leopard forums. A geek informed me there is no way to change font size within Front Row as of now. He supplied a link to complete and submit a Leopard electronic "comment card" to suggest Apple implement a change so that users can adjust the font size. I submitted the card, but I'm not holding my breath.
Despite the smaller font size, I like the new Front Row interface--much nicer than before. Plus, at least I've read on another crazed audio site, the USB software (drivers?) packaged with Leopard is better (more sophisticated, more robust) in comparison to the old drivers, hence a little better sound quality if you're using the USB outputs.