2000 DHS Questions

I just purchased (like today) a used DHS with 58000 miles. I fell in love the the car the moment I saw her. I do have a couple of questions though and was hoping someone could help.
I am interested in purchasing OnStar but when I pushed the button a Verizon message came over stating that the number had been changed. Is this an old analog system and I therefore SOL?
I have a Sirius satellite radio. Can it be wired directly into the existing stereo?
I can only find one Accesorie outlet (cigarette lighter) I am assuming if I need more I must wire them in direct or am I missing something? Has anyone wired in outlets? Any tips?
I have bugged you all enough for now. I'm sure more questions will come up in the future.
Thanks in advance for any help that can be provided.
RN

I'm not sure when OnStar changed the system requirements. I'd call OnStar directly and see if they support your DHS.
I'm sure your Sirius radio can be wired in directly. I'd talk to a local stereo shop about it. I just use the cassette adapter for my Cads.

Thanks for the help. I finally got OnStar to pick up and I can use it until 08. Not real pleased with the price. I probably won't activate it.
I have the Sirius wired up temporarily. Just not enough exta power points. Satelite, phone, etc.
Thanks again for your help. I'm sure I'll be back with more questions.