Any way to create a home media server?

I'm looking to find a way to create a media server at home so that I can stream music, photos, and video across multiple devices. I want to be able to stream content to a PS3 and an iPhone. I also want to know if I can make it require a password or something to access it, to prevent neighbors or other people that come over from accessing my content. Any help?

Yes - just buy an old computer off ebay - pentium dual core, about 2gig ram for about 50 bucks

Then buy Microsoft home server $49

Does exactly what you want including requiring a password.