Make blog recently posted about how to run an iTunes DAAP server in Linux with Firefly. Firefly (né mt-daapd) provides an open-source digital audio server that supports iTunes-compatible streaming. With it, you can stream your media from a Linux platform to any other computer that's running iTunes. Best of all, it transcodes in real time. This allows you to stream file formats not normally supported by iTunes, such as OGG and FLAC.
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