Chango is a system for cacheing MP3 files from multidisc cdrom drives. Since you can't actually mount different discs in the same physical device simultaneously, this software will cache the files you need off to a predetermined cache, so that all of the needed files will be available simultaneously.
MP3 Host is a CGI script that will gather, on-the-fly, a list of all media files by extension in (sub)folders and present a page for people to access the content. It has customizable options. Its output is updated at each load. It features hands free maintenance, and makes an effective MP3 server.
Klactoveedsedstene is a cross-platform graphical audio front-end to MPlayer. It has advanced support for album art. It recognizes embedded album art, and is also mostly able to find the correct album art from the Internet based on the Metadata tags. It features fast startup, Select and Play, an all-in-one window, and the ability to drag and drop music into the library. It supports ape, FLAC, Ogg, MP3, MPC, WAV, and WMA. It is highly configurable and stateful (remembers your window settings). All parts of the GUI can be colored. It has Album-Artist-Track view. All track columns are sortable and movable. The interface can be minimized.
1FCD-OpBSD (also known as Karma BSD) is a one-floppy OpenBSD MP3 player with functionality to mount NTFS, UDF (on DVD, CDROM, or external file), EXT2FS, NFS, MFS, and MSDOS file systems. It plays MP3 tracks, and can copy files from any disk to any disk. The software may be useful for the blind and it can also be used as a unique utility for copying files over a network (via NFS) or from any file system known to OpenBSD. USB sticks can be mounted as well. Static OpenBSD binaries can be made on other systems and used with Karma BSD.
BackPlay a program that plays music files from a folder in the background. At login, it scans a directory called "BackPlay" under the user's Music directory, and begins playing any music files it finds there in random order. BackPlay is independent from iTunes. It can be paused from an icon in the status area.
streamiumd aims to be a simple-to-use, yet feature-rich daemon that runs on a server containing MP3s and M3U (playlist) files. It requires very little to get it running (Perl and MP3::Info), runs fast even on old machines, and allows your MP3 collection to be browsed from your Philips Streamium (tm) MC-i250 or MC-i200. It can serve to multiple devices simultaneously, has its own built-in HTTP daemon, can read HTTP URLs for Internet radio from M3U files, and can run on whatever port you choose.