Obviously the iPhone was going to go with 3rd party retailers at some stage, and now apparently the iPhone is on its way to RadioShack according to the Boy Genius Report.
Apparently The Shack has announced they are to offer the iPhone 3G and iPhone 3GS as the end of this months at selects stores in New York City and Dallas Fort Worth, and hopes to offer the iPhone nationwide in 2010.
Currently Apple and AT&T retail store along with Best Buy and Wal-Mart are the only places to grab the iPhone but hopefully more will follow once the RadioShack starts pushing the iconic handset out.