Most cell phones can exchange text messages with other cell phones or computers. But often a cell phone owner has to be a registered user of an instant-messaging service to participate.
Instant-messaging rival Yahoo has alreadya similar service, available only to AT&T Wireless subscribers.
Yahoo and AOL are building a technical bridge between their instant-messaging applications and Short Message Service (SMS), a technology that lets cell phones send or receive a type of e-mail. SMS e-mails are less than 160 characters and don't have any attachments.
Instant-messaging application developers and Microsoft, the maker of MSN Messenger, have considered wireless messaging as a new source of revenue. While instant messaging is free on computers, most wireless carriers charge subscribers a fee for every SMS text that's sent or received.
But wireless messaging, popular in Europe, hasn't taken off in the United States as many cell phone carriers had hoped. Fewer than 10 million of the nation's 140 million cell phone consumers use their handsets for anything more than voice calls. In Europe, more than 1 billion text messages are sent every day.
Subscribers to five of the nation's top six cell phone providers can access AIM from their phones if they are already registered AIM users, said Derick Mains, an AOL spokesman.
For now, the new service will be limited to those participating in a trial of AOL's newest version of AIM, 5.2.