Microsoft is planning to ship its next major version of Windows–known internally as version “7″–within roughly three years, CNET News.com has learned.

 The company discussed Windows 7 on Thursday at a conference for its field sales force in Orlando, Fla., according to sources close to the company. While the company provided few details, Windows 7, the next client version of the operating system, will be among the steps taken by Microsoft to establish a more predictable release schedule, according to sources. The company plans a more “iterative” process of information disclosure to business customers and partners, sources said.Windows Vista, the oft-delayed most recent release of Windows, shipped to businesses in November and to consumers in January after more than five years of development. Vista’s gestation period was marked by shifting product details as internal priorities changed and problems arose with development.

Like Vista, Windows 7 will ship in consumer and business versions, and in 32-bit and 64-bit versions. The company also confirmed that it is considering a subscription model to complement Windows, but did not provide specifics or a time frame.Next up on Microsoft’s agenda is Service Pack 1 for Windows Vista, which is expected before year’s end.The discussion of Windows’ future isn’t surprising, given that Microsoft has been criticized by business customers for delays related to Vista. Many business customers pay for Microsoft’s software under a license agreement called Software Assurance. Windows 7 was previously known by the code name Vienna. A Microsoft representative confirmed that Windows 7 is the internal code name for the next client release of Windows.

The details were released “as part of our ongoing outreach to enterprise customers and partners, Microsoft has begun sharing plans for how they will continue to deliver value to businesses in the future…Software Assurance customers in particular,” a representative said in a statement via e-mail.“Microsoft is scoping Windows 7 development to a three-year time frame, and then the specific release date will ultimately be determined by meeting the quality bar,” according to the representative.