The new arrangement lets fans listen to games broadcast by RealNetworks over their wireless phones or personal digital assistants. Customers need to have a wireless carrier that supports SMS (Short Message Service), a text-messaging technology.
Fans will receive the local radio broadcast for whichever team they select and will be able to switch between games using voice-recognition commands or SMS.
The RealNetworks Web site says that "anyone with an SMS-enabled phone" can sign up. Nearly every cell phone sold in the United States is capable of receiving SMS messages, which are wireless e-mails of 160 or fewer characters.
The new audio service costs $19.95 per month. Customers also are charged for the minutes spent listening to the games. Although RealNetworks said in a statement that the service is available through "qualified wireless carriers," the company's Web site lists only AT&T Wireless.
A phone headset isn't necessary to get the baseball broadcasts, but would make listening to a three-hour game a lot more comfortable, according to an AT&T Wireless customer service representative. Headsets can cost as little as $5. A RealNetworks representative could not immediately be reached for comment.
The deal expands on earlier agreements under which RealNetworks has been streaming live audio broadcasts of Major League Baseball games.
Baseball has also been testing the waters with different forms of online broadcasts. Last month, it conducted its first-ever live video Webcast, covering a game between the New York Yankees and the Texas Rangers. About 30,000 people outside the local markets tuned in, 10 percent of whom accessed the stream from outside the United States, according to MLB.com.
Real Networks announced a similar plan to Webcast college football games through a deal with FoxSports.com.