
To open a video or audio file in the QuickTime Player app on your Mac, do any of the following: Play a file. I don't understand why Apple doesn't offer that feature in iTunes, and, worse, why they took this great feature out of QuickTime X. Open and play a file in QuickTime Player on Mac. Personally, I just listen on my iPhone, so I've got 2x speed for books and podcasts, which is great. Once you have it open in QuickTime 7 Player, you can then go to "Window" > "Show A/V Controls", and control the speed there (between 0.5x and 3x).
And even then, to play in QuickTime 7, you have to control-click on the song in iTunes, select "Show in Finder", and then in Finder, control-click on the audiobook track, and select "Open With" > "QuickTime 7 Player". If you've got Snow Leopard, QuickTime X (mystifyingly) doesn't have AV controls, but you can get download QuickTime 7 Player for Snow Leopard here or find an article about finding it on your OS DVD here). If you've got a pre Snow Leopard (pre 10.6) version of the OS, you can download it from. If you don't have QuickTime 7 Player, get it. I personally find the lack of integration sufficiently annoying that I wouldn't dream of using QuickTime 7 Player. iTunes doesn't have that feature, but if you're determined to do so, you could use QuickTime 7 Player. If you have an iPod Touch or iPhone, you have a double speed option there (as well as a 0.5x option).