Filed under: CellphonesThe NPD Group offered a bit of insight into the carrier-jumping habits of original iPhone buyers way back when and, as you might expect, it's now back at it and taking a stab at determining exactly where the iPhone 3G's users are coming from. According to the group, between July and August of this year, 30 percent of iPhone 3G buyers ditched their existing carrier to buy the phone, which is a somewhat significant uptick from the 23 percent of consumers overall that switched carriers during the same time period. Of that 30 percent, 34 percent of 'em switched from Verizon, 24 percent came from T-Mobile
