How to tag a file as an audio book -- for Ipod Classic categorization

Hi -- I've got some audio files (mp3) that are audio books. I wanted to classify them as audio books so that they show up as audio books in the menu of my Ipod Classic.

Right now, when I transfer them over to the Ipod via Itunes, the Ipod isn't recognizing them as "audio books," but instead as "albums".

Is there a way to move the audio files into the auidio books category in the Ipod menu from the Ipod itself?

Thanks