Real player server?
Something like that! I assume you're talking about web radio that can stream to devices. Protocols are fairly well defined, for the most part software is the least of your worries
The real kicker is PPL and PRS (I think PRS is only needed if you had live studio performances.)
Forgot to say, for size of hosting...
Will really depend on the bitrate of the files you're broadcasting.
You shouldn't need huge amounts of bandwidth as for most of these devices you use multicast and UDP so while you're not likely to be able to host from home long term you can at least reduce some costs during your startup phase.