Recommended Hardware for Streaming MP3 Radio Stations?

Silent Node asks: "I am involved with a campus radio station where the web-site, e-mail, and pretty much everything else are hosted by third parties. In the interests of both cost savings, and control, we're considering purchasing our own server, and handling things directly. Aside from hosting a nothing-too-wild web site, this server would also have to hadle about two-dozen Email accounts, a couple mailing lists, and...streaming audio. I have experience administrating Windows NT, which is why I don't want to use it for this many things on one box. Our consideration is to perhaps get a G4 and run Linux on it. I have a few questions related to this... Would it be 'easier' just to run x86 Linux? What sort of minimum specs would a server like this need (remember, being listener funded, price is a big deal)? What streaming media sofware choices would we have (MP3 streams would be prefferable, due to the wide distribution of players)? Do you forsee any 'hang-ups' I haven't mentioned (i.e.: is this even practical)?"