One of the guys on the shop ride uses his phone to track his bike rides via GPS. I think he's got a Blackberry, however, and not an I-Phone. Some limitations to the programming and I don't recall what they were...However, he seems to like it. It's kind of funny to see him ride with this great big phone-thing snapped to his handlebars (esp. compared to other more traditional bike computers), but he says it works fine.