-By The Hollywood Reporter (via Reuters)

Sirius XM Radio subscribers will be able to download software on Thursday that lets the satellite radio service's programing play on Apple's iPhone.

"Beginning tomorrow, the [iPhone] app will be available," a customer service representative for the New York-based company said Wednesday.

The iPhone service, which can also be used by iPod Touch Wi-Fi users, will be free for Sirius customers who subscribe to its Internet option. Others will have to pay about $3 month, the representative said.

The move is seen an important way for Sirius to gain and retain subscribers, by providing easier access to its news, talk, music and sports programing through means other than its traditional satellite-based platform.

Sirius already has about 19 million subscribers to its pay radio system, but its biggest source of new user is the when consumers buy cars with satellite radios built-in.

But last month, Sirius attributed a quarterly decline in customers to poor automotive sales, and predicted a "noticeable hit" to its subscribers in the current quarter for the same reason.

Sirius faces both big opportunity and tough competition in Apple's app store. Apple has sold more than 40 million of its iPhones and music-playing iPod Touches to date, with a substantial portion in U.S. where Sirius's nationwide broadcasts are concentrated.

But several of the most popular applications available in Apple's app store include free Internet music services such as Pandora and Slacker, as well as iheartradio, which is supported by the terrestrial radio industry.

Sirius, whose subscribers pay a fee of about $13 a month, had previously said the app would launch in the second quarter of this year. An official spokesman for Sirius, one of the largest U.S. subscription services, did not return requests for comment.

Shares of Sirius rose in afternoon trading, climbing to 34.8 cents a share, up about 8 percent.