Is there a link to an audio of the arguments?
No. The judges would not allow audio recording this time.
Link to the audio will probably be available tomorrow. www.scotusblog.com has been overwhelmed at the moment, and their bloggers said that the court will provide audio tomorrow (and they will have the link).
Sounds like some good news and some not so good news.
Good news: looks like it will probably be incorporated
Bad news: it will probably be the through the due process clause of the 14th amendment and not the privileges and immunities clause. Just means, that to gain more access to our right, we’ll have to sue. Equal and due process, hopefully will help out our friends where their rights are infringed with bearing, and not just keeping, their arms (like my home state here in MD where they get to decide through no real standard).