SCOTUSBlog has a very good preview of the oral argument in Comstock. How Appealing has a roundup of some media coverage. And Sentencing Law & Policy has Berman's initial thoughts in anticipation of the argument transcript being issued later today.
I'm most curious to see if the Justices frame the jurisdictional issues as involving the Commerce Clause (like the district court and 4th Circuit did) or if the Justices see things in terms of the Necessary and Proper Clause (like the government continues to contend the case should be viewed as being about). In a completely unsupported random wild guess, I'll set the over/under on number of times the "Commerce Clause" is mentioned by a Justice at 15. If there are more than 15 mentions, Comstock wins. If there are less than 15, the government wins. It's probably best I am not a bookie, though.