Don't you just hate it when publishers, publicists, and authors deface a book they send you by stamping For Review Only: Not for Resale sign on the book pages? How do you feel about this?
It is not illegal to sell an ARC. Booksellers and publishers over the years have had a silent agreement that they wouldnt sell them before or during the first 3 months of a release of a title.(This is written in stone, just from my experience)
www.abe.com and www.biblio.com have thousands of them listed, and if this was "illegal" they would have been fined/shut down by now.