Yahoo Inc. on Monday said it is working with Research in Motion to pre-install Yahoo's instant messaging software into RIM's popular BlackBerry wireless devices.

Under the agreement, BlackBerry devices in the "coming months" will ship with the full-color, graphical Yahoo Messenger client. The deal builds on Sunnyvale, Calif.-based, Yahoo's strategy of extending its core desktop services to mobile devices.

The Yahoo! Messenger service on the BlackBerry platform will allow consumers to see who in their buddy lists are online, send and receive instant messages, have multiple conversations at once and participate in online conferences.

BlackBerry users today can access Yahoo's search, news and sports services through the Yahoo Mobile Internet portal.

In other news, Canada-based RIM on Monday said it had joined AOL's Mobile Developer Program in order to support the AOL Instant Messenger and ICQ instant messaging services on the BlackBerry platform. RIM has also provided BlackBerry users with access to the email service of the Dulles, Va., portal.

The AIM and ICQ services for BlackBerry will be available through AOL authorized carriers.