Microsoft will allow songs to be sent via Wi-Fi: People can sample each other's purchased song libraries on the upcoming Zune music player by permission. Songs are allowed to be transferred--another story mentioned that not all songs would work this way--can be listened to three times over three days before being purchased for what's expected to be 99 cents. There will also be a subscription service, the price of which hasn't been announced. It will also let you share photos among Zune users. You can turn off this feature or not accept shared music and photos, too.
One might suspect that the subscription service would allow any song downloaded by subscription to be transferred to any other Zune user who also had a valid and active subscription, no? This is a feature of MusicGremlin, which can transfer songs downloaded via its subscription service to other MusicGremlin subscribers. (While the MG can play other DRM'd content from other services, those songs can't be transferred among users.)
In fact, the answer is no. The Electronic Frontier Foundation read the fine print, and Zune apparently cannot play other Microsoft Play4Sure protected content. Holy mackerel, if that's true, that breaks Microsoft's model for media protection--that all Plays For Sure devices play stuff for sure. Further, BoingBoing analyzes this Microsoftee blog post to realize that Creative Commons-licensed content could be wrapped in protection in order to be played on the devices, which would be a violation of their copyright terms. Medialoper has more detail. (The EFF also notes that the Zune's creator suggests that users could rip video using methods illegal under the Digital Millennium Copyright Act, an act that the EFF finds offensive, as do I.) Update: The Zune won't wrap DRM around unprotected content, it turns out, but it will prevent this media from being transferred over Wi-Fi among Zune players without stapling on the three-day, three-playbacks restriction.
Pricing on the Zune is expected to be $250 to $300 with a 30 GB drive, full-screen 3-inch display, FM tuner, and Wi-Fi. It won't work with Macs.