This is an app which has live timing, it is really good but you have to download the apk to your phone. There is also a computer version :) And best of all, it’s free!
Red Bull have just released their app on android, it links with the red bull spy they use on Twitter and has general F1/Red Bull news too. And it’s free!
Team F1 Free 2013 is great for general info and news, and checking up on things like session start times (although those are on the F1F calendar as well).