There's also http://BCycle.Me for all mobile phones. Much better interface than the official app.
Best Smartphone App - 2011
There's nothing worse than showing up at your neighborhood B-cycle station, picnic basket in one hand, book of love poems in the other, and discovering that the romantic afternoon you had planned with the girl of your dreams is foiled because all of the bikes are rented and now you'll never get to second base. Luckily, B-cycle's app is designed to prevent just such a disaster. Using your phone's GPS, it tells you which B-cycle stations are closest and how many bikes are available. Score!