App Store payments are not reported to the IRS and you will not be receiving a 1099 in the mail from anyone. App Store payments are treated as sales commissions rather than royalties, according to the iTunes Royalty department of Apple. You are responsible for reporting your earnings and filing your own payments for any sums you have earned from App Store.
Alright, I’m tired of this. I’m going to go home tonight and go over my deposit records and do a bunch of math and figure out definitively whether anything has been withheld.
Apple couldn’t possibly make the App Store payment process less informative or more confusing for developers.