
The interoperability programme is currently available as a limited beta in a series of countries including the UK and US. The final product will be released in the coming months, the two companies said in a joint press release.
Users can sign up for the beta on the Microsoft and Yahoo! webpages. The sign-up information wasn't available as of press time. A Microsoft spokesperson said that it would be posted later on Wednesday.
The beta period is intended to allow for scalability testing of the new service, the spokesperson added.
“This first-of-its-kind interoperability between consumer IM leaders Microsoft and Yahoo! gives our customers tremendous control, convenience and freedom in their Web communication experiences with Windows Live,” said Blake Irving, corporate vice president for the Windows Live Platform with Microsoft.
“We’re proud to deliver this latest advancement in IM services that empower people to communicate with virtually whomever they want, wherever they want and whenever they want.”
Microsoft and Yahoo! last October promised to provide interoperability between their respective instant messaging services. The project was originally scheduled for completion by the end of last month.
The providers claimed that their combined services make for the world's largest instant messaging network of 350m subscribers.