CEO Steve Jobs is slated to take the stage at 10:00 a.m. local time at the company's Worldwide Developer Conference to officially launch the iPhone 4G.
The phone will reportedly feature a number of enhancements over its predecessor, the iPhone 3GS, including higher screen resolution, a front-facing camera, and a longer lasting battery.
The phone, of course, is also expected to support 4G data transmission, which in theory is considerably faster than the current, 3G standard. But it's an open question as to when Apple partner AT&T plans to fully deploy a 4G network.
Sprint last week rolled out the Google Android-powered Evo—the market's first 4G phone.
Apple has often used WWDC to launch new products. The fact Jobs is returning to the forum after a year's absence is helping to fuel speculation about the iPhone 4G and possibly other new gadgets from Apple that might be on display.
Whether at WWDC or at a later event, the betting is that Apple will indeed launch a faster, 4G version of the iPhone, running iPhone OS 4.0, at some point in 2010.
Just weeks after an Apple engineer left one on a barstool in California, another iPhone 4G prototype was spotted in mid-May.
Bloggers at the Vietnamese tech site Taoviet posted pictures of a device, labeled APL0398, that was similar to the phone lost in March by engineer Gray Powell.
Adding to all the speculation is Wal-Mart's move last week to cut the price of the 16GB iPhone 3GS by 50%, to $99. The price cut may indicate the retailer is looking to clear inventory in advance of Apple's launch of a new phone.