Mike Kozak of US Cellular like the EAA AirVenture Oshkosh 2011 application. It has show shedules, exhibitor schedules, maps, camping information- you name it - everything to make planning your adventure easy.
There's also an EAA Radio app, that lets you listen to streaming content, twenty four hours a day.
And you can't go to EAA without download a free weather app or two. Mike likes the AccuWeather app.
And of course, navigation tools are especially helpful, available on both Android and iPhone.
US Cellular has a booth at EAA AirVenture, so look for them if you need any help with your phone.