Engadget reports that tipsters with access to the retail inventory computers at AT&T Wireless stores have spotted listings for a 16 GB iPhone — something iPhone aficionados have been waiting for since the 16 GB iPod touch was released last fall. An update posted by Engadget at 4:25 a.m. suggests the release could come as early as this morning:

We just received word from multiple sources that the O2 staff has been notified of the 16GB iPhone launch at 1:30pm UK time. Price: £329. That will likely translate to $599 in the US like the original 8GB iPhone. (link)

Meanwhile
MacRumors
, which last week passed along an unconfirmed report that three new MacBook Pro models had appeared in Best Buy’s inventory tracking system, has provided screen shots to back up that claim. They show an in-stock date of Feb. 10 and three price points ($1999, $2499, $2799) that are the same as the current MacBook Pros. The new models are expected to have multi-touch trackpads and Intel Penryn chips.

The reports have led some to speculate that Apple may have timed the new releases to pump up sales in Apple’s second quarter, traditionally the slowest for PCs. Apple’s stock price could use a boost, having dropped nearly 30 points since the company issued its conservative Q2 earnings projections.

Others speculate that the late release of the 16 GB iPhone means that they will have to wait a bit longer for a 3G iPhone.