I was paging through some web sites and came across this one. It has live streaming audio of Approach, Ground, and Tower frequencies on here. Included are Cincinnati/Covington (KCVG) and Port Columbus (KCMH). Look under the Class B tab for Cincinnati and the Class C tab for Columbus. I'm glad I found this site, because I was getting ready to shell out about $150.00 for a scanner to listen to this stuff.
Here is the link if anyone's interested: