Microsoft said Wednesday it would release the protocols for its MSN Messenger program to allow other instant messaging applications to communicate with MSN users. The move continues the public relations war with America Online, which has repeatedly tried to block Microsoft's program from contacting users of its AOL Instant Messenger program. AIM has more than 40 million users. Microsoft said today that 1.3 million people are now using its service. The fight between the two companies started when Microsoft figured out how to tap into AOL's wildly popular service. AOL had made some of its code available to Unix programmers, but has since removed many links to that code from its site. Those moves by AOL have sparked criticism of the company from the "open source" movement, and, not surprisingly, from Microsoft, which has argued that consumers would be better served if all instant messaging programs used a similar protocol. The Internet Engineering Task Force (IETF) does have a working group on the issue, but AOL has not yet said that it would definitely abide by whatever protocol the IETF produces. AOL has agreed to work with the IETF. In a release, IETF officials lauded Microsoft's move. "We are delighted that Microsoft is publishing the specification of the MSN Messenger Service protocol as an IETF draft. The publication of different protocols helps us in evaluating our Requirements document and in informing our development of robust, open protocols for Internet-wide interoperability in this area," said Vijay Saraswat, co-chair of the IMPP Working Group of the IETF. "In this spirit of open protocols that benefit the entire Internet community, we strongly encourage other vendors to publish their protocols." Microsoft said it would make the protocol available to the IETF by the end of the month, and said developers would be able to use it with their products. Microsoft also said that it would support the IMPP protocol when it becomes available. At least three companies -- Prodigy Communications, Tribal Voice, and PeopleLink -- have backed the Microsoft move. Is Microsoft releasing its specs through genuine virtuousness, or is it all just PR? Send your opinion to the Mailroom.