Update: As of this afternoon, the ship times are all back to 1 day. Perhaps the inventory lag was related to weather events or other externalities.
Customers looking to buy an iPhone 4 from Apple's online store will now have to wait 1-3 days for their handset to ship. This lengthened ship time extends to every model of the iPhone 4 that Apple sells. This across-the-board delay may be a sign that iPhone 4 inventory is dwindling as Apple prepares to launch the iPhone 5 in the upcoming weeks.
Rumors suggest the iPhone 5 may have the faster A5 processor like the iPad 2, an 8-megapixel camera and both CDMA and GSM connectivity. It is expected to be announced at Apple's fall event later this month and go on sale sometime in October.