The announcement comes as the two await regulatory approval for their deal. On Monday, XM Chairman Gary Parsons said the $4.7 billion sale should close this year.

Yet, the deal still has significant hurdles to clear. The companies must convince the Justice Department that it is not anti-competitive and the Federal Communications Commission that the combination would be in the public interest.

Sirius CEO Mel Karmazin said the new channel packages show that combining the services would benefit consumers because they offer "more choices and lower prices."

Currently, XM and Sirius each charge a flat subscription fee of $12.95 a month for service, and neither lets subscribers pick individual channels a la carte.

The promised additional post-acquisition subscription options range from $6.99 to $16.99 a month, with add-ons as low as 25 cents per channel.

Offerings by the combined company would include:

•A $6.99 a la carte package with 50 stations from those offered by either XM or Sirius, plus additional non-premium stations from that service at 25 cents each. Premium programming, however, such as pro sports or Howard Stern's show, would cost more.

•A second a la carte plan that would let customers pick 100 channels, mostly from one service, plus a selection of "best of" channels from the other, for $14.99.

•A content-specific package, such as "mostly music" or "news, talk and sports," for $9.99.

Existing satellite radios could accommodate six of the eight new packages being offered. But consumers who want to purchase one of the two a la carte options would have to buy a new receiver.

Karmazin says the company will promote the new package choices at retail outlets, as well as with detailed information on each of their websites.