Perhaps in response to some recent reports noting that the shipping times for the iPhone 4 had slipped from 24 hours down to 1-3 days in the US, Apple has apparently removed shipping estimates from from their Online Store for all products. Prior to today, the company displayed estimated ship times for their products but this has been removed. No explanation has been given for the change but the Apple Store did go down overnight for maintenance so it’s entirely possible that this was the reason.
Lengthening of the shipping times for established Apple products could sometimes be used in the past to predict when a new product will launch. This move essentially now removes that predictor by simply stating that a product is in stock rather than the length of time it will take to ship. Given that sales figures of a product can decrease dramatically when rumors of a refresh occur, Apple may be trying to remove this occuring.
You can see comparative screenshots of what the Store used to look like in the example image below via BGR.