Hope the title clarified enough but Microsoft and AT&T are running a promotion now and if you buy a Windows Phone between 5/1 and 6/26 you get 3 months of Zune Pass for free. “A 3-month Zune Pass gives you access to music from the over 11 Million (US) songs in Zune Marketplace. You can download music to your Windows Phone 7, Xbox 360 console or PC. Plus you can download 10 free songs a month to keep.” I still think it should come with every phone regardless, but it’s still a good promotion.
The link is here. The FAQ does state you only have 30 days from the date of purchase to redeem it.