There's a shuttle service from the Airport ($15/one way, $25/round trip) and taxi service available ($25 to Downtown). You have to reserve the shuttle but the Taxis are available 24/7. Here's the Shuttles/Taxi/Public Transit Page from the Airport's web site. (http://www.cvgairport.com/Ground_Transportation/Shuttles_Taxis_Public_Transit.html)

I hope this helps :) I haven't decided yet if I'm going to cab or shuttle yet. I'll probably decide closer to the date and once I know if anyone else is arriving on Wednesday.