Yup. I have an Airport Express with Airtunes. Of course I use iTunes which detects the box on the network (its wireless, but can be wired too). Then iTunes shows a pull-down menu for each wireless audio station. Such as "Kitchen" or "Living Room". Then I can stream internet radio or from my library.

But thats one method. I am sure by now there are tons of options out there in various configurations.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car