Sirius Satellite Radio is not available in Hawai'i.

Stewart, who has parlayed her success at homemaking advice into a magazine, TV show and merchandising empire, has dabbled in radio work before, making 90-second "Ask Martha" radio segments.

At a news conference to announce the venture, Stewart said her connection with radio stretched back to her childhood, when her family was the last in her neighborhood to get a television set.

"I don't know about you, but I was raised on the radio," Stewart said. "I'm very excited about this. ... Of all the things that I have done in the last few years with Martha Stewart Living Omnimedia, radio is actually one of the most enjoyable."

For Sirius, the deal with Stewart is the most recent effort to compete with its much larger rival in the emerging satellite radio business, XM Satellite Radio Holdings Inc.

Earlier this month XM reported that it had 3.8 million subscribers, while Sirius' most recent subscriber count was 1.2 million.

Both Sirius and XM are still suffering deep financial losses and are spending aggressively to lure customers to their services, which cost $12.95 a month and require the purchase of special receiver units, which can only receive either Sirius or XM signals.

Both Sirius and XM offer dozens of commercial-free music channels as well as numerous talk channels, many of which carry advertising.

Stewart's channel will also carry advertising. The companies declined to provide other financial details other than to say the arrangement would last for four years.

The channel is expected to launch later this year, after a legal restriction on Stewart's ability to work is lifted. Following her release in March from five months in prison, Stewart is serving five months of house arrest at her sprawling Westchester County estate, north of New York City.

Last week a judge declined Stewart's bid to be allowed to leave home 80 hours per week for business. Under the original sentence, she is allowed 48 hours per week.

The companies did say that Stewart herself would also appear on the channel, which was expected to be called Martha Stewart Living Radio.

Last week Stewart appeared at a magazine industry awards ceremony as two magazines published by her company, Martha Stewart Living Omnimedia Inc., won honors for design and general excellence.

Two TV deals involving Stewart were also announced in the past few months, while she was still in prison: a daily cooking show was announced in December, while the "Apprentice" show was unveiled in February.

Scott Greenstein, the head of entertainment and sports programming at Sirius, said that Stewart's channel would "provide women with the definitive complement to their lives and lifestyle."

Chance Patterson, a spokes-man for XM, said that his company had spoken with Stewart's representatives but declined to make a deal with her.

Sirius' shares fell 7 cents to close at $5.08 in brisk trading yesterday on the Nasdaq Stock Market, while XM's fell 31 cents to close at $27.19, also on the Nasdaq.