Microsoft plans to begin the roll-out of Windows XP Service Pack 2 (SP2) sometime next month, bringing long-awaited improvements in security to Windows XP users.

Work should be finished on the security-focused patch next month. Will Poole, head of Microsoft's Windows client business, is expected to announce today that it will be released to manufacturers in August, starting the distribution to users of the delayed update.

The delivery will start with the launch of a new version of Windows Update. The new update service includes smart downloading technology that will allow users to interrupt the large SP2 download and resume it later, especially useful for users of dial-up Internet connections. The latest test version of SP2 was 264MB, though the final version will be smaller, insiders say.

Although Microsoft has called Windows XP SP2 a service pack, analysts have said that the update really is comparable to a Windows upgrade. SP2 contains bug fixes and updates, but it also offers new features and makes significant changes to the Windows software in four main areas: network protection, memory protection, email security and browsing security.

Microsoft claims that the service pack will represent one of its most broadly tested products to date, with hundreds of thousands of people having tried out the service pack since a beta version was first released in December. Microsoft has warned that Windows XP SP2 could break existing applications though.