More details are emerging about Sony (NYSE: SNE) Ericsson’s (NSDQ: ERIC) unlimited music service, which sounds a lot like Nokia’s (NYSE: NOK) upcoming “Comes With Music.” Quoting recording-label sources, CNet reports today that the service is expected to launch within the next week, and that it’s through a partnership with British firm Omnifone, which provides unlimited music downloads to mobile service providers. Apparently, all four major labels have signed on, which beats the three Nokia has negotiated (it’s missing EMI). Nokia’s Comes With Music works by providing a year’s worth of unlimited downloads when you buy a device (which are side-loaded only, but one perk is that you’ll continue to own the music once the year ends). Details on how Sony Ericsson’s program will work are a bit cloudy, although it is supposed to include a subscription-based service.