Alongside iOS 7 beta 4, Apple released today iTunes 11.1 beta for the Mac. The release brings the new iTunes Radio service that Apple introduced at WWDC last month. iTunes Radio allows you to listen to custom radio stations and gives you the option to buy the songs you like right there. It is free with ads; iTunes Match subscribers do not see any ads.
Up until today, the only way available for testing iTunes Radio was through iOS 7, but with today's beta release of iTunes, users can now test it on their Macs.
iTunes 11.1 beta for Mac is available directly to developers from Apple's Developers website.