i just bought the igeocacher application for my ipod touch. it is great! it takes your gpx file from groundspeak, uploads it to the ipod, and all the cache info is there at your fingertips.
check it out yourself: http://www.ayefon.com/geo/index.cfm
you have to have wifi to load them, but then they are stored for use. the great thing is it loads the whole list. the groundspeak program at this point, makes you load each cache individually.