I'm nearing completion of development of an EV tracking app for iPhone. It allows you to set EV goals for a Pokemon and track EVs gained based on its held item, Pokerus, and Pokemon defeated.
EDIT: EVTrack v1.0 is released today and available here: http://bit.ly/EVTrack1
If anybody's interested in helping beta test the app, sign up here: http://bit.ly/jQAd1l. Please note you should be willing to provide constructive feedback. If you don't want to commit to being a tester, feel free to leave any suggestions here for what you'd like to see in this app. I'm not currently running a beta test for this app.
EDIT: EVTrack v1.0 is released today and available here: http://bit.ly/EVTrack1