Music-related web-based apps.

Ampache is a web based audio/video streaming application and file manager allowing you to access your music & videos from anywhere, using almost any internet enabled device. Ampache's usefulness is heavily dependent on being able to extract correct metadata from embedded tags in your files and/or the filename. Ampache is not a media organiser; it is meant to be a tool which presents an already organised collection in a useful way. It assumes that you know best how to manage your files and are capable of choosing a suitable method for doing so.
AmpJuke will act as your streaming server. Besides music streaming AmpJuke can fetch album covers/images/lyrics automatically using various webservices from last.fm, Bing! and other sources. Scan+import tags from as many tracks you like, use the favorites as well as a bunch of other personal settings to customize the way AmpJuke operates.
Impleo is a simple PHP-script for managing your record collection. It's possible to add, edit and delete records. Each record contains the name of the artist, title of the record and year of release. In addition to this, it's possible to add any kind of detail of your own choise.
kPlaylist is a free PHP system that makes your music collection available via the Internet. kPlaylist is a music database that you manage via the web. With kPlaylist you can stream your music (ogg, mp3, wav, wma, etc.), you can upload, make playlists, share, search, download and a lot more.
Podcast Generator is a free web based podcast publishing script written in PHP: upload media files (audio-video) via a web form along with episode information and automatically create podcast w3c-compliant feed including iTunes specific tags. It also features a comprehensive web administration.