Microsoft announced today that the next version of its popular Office software will be delayed again, the second time in three months. The company now plans to deliver 2007 Microsoft Office, as the application suite has been renamed, to “business customers” by the end of the year.

The retail version of 2007 Office will be available to consumers in “early 2007,” according to the company’s announcement. Previously Microsoft promised the retail version by January 2007.

Microsoft is delaying the product so engineers can better incorporate feedback from the 2.5 million Office 2007 beta testers, a spokeswoman with Microsoft’s public relations agency told our colleagues at IDG New Service. “What they want to do is to… give themselves a bit more time to make the product as good as it can possibly be,” she said.

And according to another Microsoft spokesman: “The development team looked very critically at the work items remaining and the new timeline reflects what we believe to be a realistic amount of time to accomplish the remaining work.”

The latest Beta 2 version of Office 2007 was made available in May, a little earlier than expected. The software giant previously had promised the product by this October.

This is the second delay for the product in just over three months. Last March Microsoft moved the new Office release back to keep it in line with the arrival of the company’s new Vista version of Windows, which has also suffered a series of delays. This slip raises questions about whether another Vista delay is imminent as well.

Last month Microsoft Chief Executive Officer Steve Ballmer said the consumer launch of Vista could slip past his company’s January launch date.

The most recent delay may hurt PC sales during the holiday season, traditionally system vendors’ strongest sales month. Even though many manufacturers are likely to offer their end-of-year customers coupons for free upgrades to the new version of Office when it becomes available, many businesses and consumers are now more likely to wait until early next year to make their PC purchases.

Earlier this week, Microsoft released a Web-based version of Office 2007 that users could test within their Internet Explorer browsers.