Windows/Mac/Linux: Access your music from afar with Sockso, the open-source music server. The simple, no-install-need setup can make your music available for the next trip you take out your door.
Sockso is designed to be extremely user-friendly. There is no installation process, beyond extracting the archive and running the file inside. When you run it for the first time, you select the folder your media resides in, whether your files are in MP3, OGG Vorbis, Flac or WMA format. Once Sockso is up and running, you'll need to open a port in your firewall for it in order to access it outside your network.
After scanning your media and making sure the firewall has an open port, all your interactions with Sockso take place through the web-based interface. You can browse your collection, make playlists, download your music to pass on, and get a breakdown of your music by more recently played/popular, and so on. You can even set up accounts for your friends and accept uploads if they've got music to share with you. Sockso is an open-source media server with versions for Windows, Mac, and Linux.