Microsoft has launched a campaign to open its software to outside developers.

The company vowed to adopt four new goals which it hopes will foster better interaction with other vendors and developers.

Microsoft's Interoperability Principles include improved connections with third-party products, better portability of data, support for industry standards and a commitment to work with open source vendors and developers.

"Customers need all their vendors, including and especially Microsoft, to deliver software and services that are flexible enough so that any developer can use open interfaces and data to effectively integrate applications or to compose entirely new solutions," said Microsoft chief software architect Ray Ozzie.

"By increasing the openness of our products, we will provide developers with an additional opportunity to innovate and deliver value for customers."

The programme will apply to much of Microsoft's existing enterprise software offerings, most notably Windows Vista, Server 2008, SQL and Exchange Server, and Office 2007.

Microsoft's lack of willingness to open its products to outside groups has long been a point of contention between the company, its competitors and regulatory groups.

This attitude was partly responsible for the €400m judgement the company incurred from the European Union in 2004.

More recently, Microsoft has come under fire from the EU and open source software advocates for its high royalty rates and patent-sharing programme.