Where can I see what will be on Sirius? DogstarRadio.com has the full SIRIUS schedule in a tv guide style format.
Where can I see what song I heard earlier? ItsOnSirius.net allows you to search playlists by song and artist title. They will soon allow you to see what was played on a particular channel over a particular timespan (like when you were driving home). itson.siriusbackstage.com also allows you to see what is now playing and search by song or artist. In the past they have supported advanced searches and reportedly will again.