GNUdap is a project to build a userspace driver to interface Linux with proprietary-protocol USB MP3 players and mass storage devices. Currently, GNUdap supports only the "Perstel,Inc. CHIC MP10". GNUdap is also an experiment to test the advantages of a strongly-typed programming language and of the functional programming paradigm in hardware development. GNUdap currently supports all features supported by the official program provided with the Chic, and has some additional features, like being able to transfer MP3s directly to the PC.
BiblePlayer is a freeware program that lets you read and listen to the Bible on the iPod. It includes daily devotionals, bible reading plans, bible stories, and other modules. Each reading is linked to an audio file, making it an integrated experience. (Audio CDs are sold seperately.)
BeatPacker is a simple Python script that uses an M3U playlist to generate a temporary folder filled with files that can be easily transferred to a portable music player. It's designed to be used as a target for drag-and-drop, a nautilus-scripts right-click action, or similar purposes. A Windows installer is available.
Mychoonz is an MP3 player implemented in AJAX. It allows you to listen and organize your music within your browser, anywhere, anytime, as long as you've got an Internet connection. The idea is similar to projects such as Ampache or Mp3Act, but it focuses more on user interface rather than features.
Crossfire is a Firefly Media Server client written for the Apple iPhone and the iPod touch. It has support for streaming, browsing, and searching music content. It supports both Mobile Safari and FireFox, but can be configured for various other devices such as Windows Mobile, Symbian, etc.
Beets is a media library management system designed for obsessive-compulsive music geeks. It catalogs your collection, automatically improving its metadata as it goes using the MusicBrainz database. It also downloads cover art for albums it imports. Then it provides a bouquet of tools for manipulating and accessing your music. Beets also includes a music player that speaks the MPD protocol, so you can play music in your beets library using any MPD client.