Just in case you're one of those people who need to obsessively check on his or her Battlefield 3 stats while waiting for the bus, EA has released a Battlelog app for iOS devices. The free app is now available, and keeps track of your friends' activity, leaderboards, and news.
The App features list the "full-fledged Battlelog platform." That includes a Battle Feed for notifications when your friends unlock weapons or awards, a Com Center to check who's playing and on what server, your own personal stats, leaderboards, and updates from DICE.
Reviews seem fairly positive for the app, which at the moment is only on iOS devices. The Android store doesn't have its own Battlelog yet, so you'll have to rely on the various third-party stat apps if you happen to use a Droid phone.