Earlier this month we revealed that a selection of privileged websites were receiving hands-on demonstrations of GTA IV, and that previews were due to be published some time around the 27th of this month. We now have a confirmed date for those previews, and that is Thursday 28th February, which is two days from now. You can expect previews from Kikizo, GameSpot, IGN, and the usual suspects. We don't know the exact time of release yet, but expect it to be around 5PM or 6PM (GMT).
UPDATE: TeamXbox reports that the previews will be released at 6PM GMT / 10AM PST. We are expecting around 10 new screenshots, and you can find them all here at GTA4.NET (in their original, high quality, high resolution format) as soon as the previews go online.