The iPhone is twice as reliable as the Blackberry after one year of ownership, a new study by SquareTrade finds. SquareTrade, which sells extra warranties for cell phones and other devices, looked at the failure rates of 15,000 phones covered under its plans. The malfunction rate for iPhones after one year is 5.6 percent, compared to 11.2 percent for the Blackberry and 16.2 percent for the Treo.  More from MobileCrunch