OnlineSequencer.net - OnlineSequencer.net is an online music sequencer that allows users to create beats and music tracks.
GoatTracker - This is a crossplatform C64 music editor.
AudioSauna - AudioSauna is a full-featured audio workstation for making music online.
Jeskola Buzz - Jeskola Buzz is an all in one digital audio workstation that allows you to edit music with the perfect blending by using modern tools and technology.
Jummbox - A modified Beepbox that have more stuff then Beepbox. It can be used just like Beepbox. The features of Jummbox is the same of Beepbox's features, but Jummbox have more stuff to offer.
ButtonBass - ButtonBass is an online music development toolkit that lets you play with virtual instruments and effects in a fun and interactive way.