Disclaimer: it's not a dedicated Whitney app (though you can download 3 maps for its trails), it's iPhone only & I'm not betting the bank on it... but a real handy app is Maplets, $3 from the Apple Store.
http://mobilemaplets.com/ It's a must-have as far as I'm concerned, really useful. You have to spend a little time downloading the maps - I have maybe 1000 in mine for the state of California. It covers USFS & NPS maps, state & county park maps, ski resort maps, public transportation & bike routes, street maps, etc. I don't leave home without it - I've got the map in my pocket if I pass by something I want to explore.
Topo Maps is also useful, $8, very simple.
http://topomapsapp.com/Mountain Project has an interesting app. I haven't used it too much but it looks like I'd better getting downloading pronto. Apple and Android.
http://www.mountainproject.com/mobileApps
