On its Windows Service Pack Road Map page, Microsoft has updated the expected date for Windows XP SP3 to the first half of 2008. This represents the latest in a string of delays. SP3 was originally stated for the second half of this year, which was then pushed back another year to the second half of 2007.
No official reason was provided to explain the recent delay, but a Microsoft official did explain back in January that the company's main focus is on shipping Windows Vista. Some may believe that the delay in SP3 release is an effort to encourage more users to upgrade to Microsoft's newer, more secure OS.