AOL Insta-Spams MSN Messenger.

The latest shot fired in the instant messaging war between Microsoft and America Online came in the form of a mass instant message Wednesday night. AOL fired off a semi-ominous message -- combined with a pitch for AOL_s own software -- to users accessing its chat system with Microsoft_s competing instant messaging software. "Please be advised that you are currently accessing the AOL Network using unauthorized software. You can download a FREE, fully featured, and authorized client, here," the message said. The message, a unique form of targeted instant spam, then linked Messenger users to a site for downloading AOL_s competing instant messaging software. Instant messaging is similar to live email in which users can summon each other instantly and exchange messages in real time. It_s similar to open chat rooms on the Net, but is specific to two or more acquainted users.