You can of course download Duets II from iTunes, Amazon or wherever else you download music. But (in part because of parallel issues involving relative prices of ebooks and printed books) I'm providing a link only to the Amazon.com page for the CD, where it's currently $3.00 cheaper than the download.
Tony Bennett was one of my earliest favorites (along with Dinah Washington and Peggy Lee) and has remained with me through all the changes in media (45s, LPs, CDs, MP3s) and (other people's) styles. Not long ago, one CD of vintage Bennett material survived many months of almost daily play in the changer in the car, and I'd like to single out this particular line-up of songs to recommend today. It is in fact no longer available as a CD, but as an MP3 album it's going strong. It's what survives (along with some 'CD extras') of Bennett's 1965 LP If I Ruled the World--Songs for the Jet Set. It's very much the pop Bennett (as distinguished from the jazz, well represented in the compilation bearing that title), and I recommend it in its totality, even though you'd have to go to another album of the same era (or a greatest-hits compilation) for two indispensable pop cuts ('The Good Life', 'I Wanna Be Around...').
And, if you'd like even more, take a look at Bruce Ricker's 2007 tribute while it's available on Netflix instant play.