The SDK will include Active X controls for contact views and message views, Host APIs and tools for administration.
It will also ship to IM clients with Exchange, the already released MSN Messenger product, and a client based on the SDK.
Later this summer, the company will ship an add-on for its Outlook 2000 e-mail client that integrates presence information. And deSouza said presence information could go even further.
"In the future, there's no reason why applications like Word," wouldn't have this feature, he said.
That would allow a user to, for example, look up the author of a document and find out instantly whether he or she is online, or find out who else is working on the document.
Releasing the SDK for IM will also allow third parties to develop their own applications that use presence information. For example, a workflow application could use presence information to find out who on a list of authorized people is available to approve a document, and route it accordingly.