Garage|Shadow, from Unify4Life, turns a BlackBerry or any other Bluetooth enabled cell phone into a remote control for garage door openers. It even has an "automatic open" feature that senses when you have returned home and opens the door automatically.
Pretty slick idea, though I have no first-hand experience with its reliability. One thing that occurs to me is that cell phone batteries run down much, much faster than the batteries in a standard remote, so you'd want to make sure that you could recharge your phone's battery outside the house before relying exclusively on the Garage|Shadow.
Garage|Shadow should be available for sale in April at a cost of about $30. I'll post a review as soon as I've been able to test it out.