Microsoft is going to release Windows XP Service Pack (SP) 3 via its Automatic Update (AU) service on Thursday July 10, company officials confirmed this week.

The client team has been vague about when it planned to push the latest version of XP to users. “Early summer� and “sometime soon� were favorite comebacks when officials were asked for an AU timeframe for SP3.

Customers who have automatic updates turned on but who don’t want XP SP3 to be downloaded to user desktops this week — for whatever reasons — need to deploy the Microsoft Service Pack blocker toolkit to delay pushed-delivery of SP3.

While Microsoft will begin pushing SP3 tomorrow, not all users will receive it immediatly, as the company will be staggering the rollout.

Microsoft has postponed and temporarily halted the distribution of SP3 a couple of times this year because of compatibility and performance problems.

Meanwhile, speaking of problems, Microsoft’s newly launched Windows Vista Compatibility Center still is down for the count. Microsoft officially launched the new portal site designed to help Vista users determine driver and application compatibilty status of products they want to deploy with Vista. The site was supposed to go live on Tuesday and, as of Wednesday mid-day, was still not operational.