SiriusBackstage reported yesterday that SIRIUS plans on offering an online-only subscription called "Sirius Internet Radio Plus". The service will offer CD-quality sound on the music channels and select talk channels including Howard 100/101 at 48kbps.
This will cost $12.95 if you are not already a subscriber and you can purchase up to 3 additional subscriptions for $6.99 each. Existing Sirius subscribers can upgrade to SIR Plus for an additional $2.99 a month. The $2.99 is just for one of your ESN's however, so if you have seperate SIR accounts on each of them you'll have to pay $2.99 for each to upgrade. As far as we know Sirius does not have any plans to offer channels on the new service that aren't available via your Sirius receiver.
Subscribers are not required to upgrade to the new service, if you are happy with the current online streaming (which lacks the talk channels) you can stick with that, which is still free.
It is not clear exactly which talk stations will be included, other than Howard, but the speculation is that the sports channels will not be included. People on SBS are complaining about the price, arguing that this should be a free upgrade for people who already subscribe.