Last.fm Lib .Net is a code library for the Last.fm API written in VB.Net 2008, but it can also be used with C# and ASP.NET. It provides a complete implementation of versions 1.0 and 2.0 of the API, the Radio API, and the Audioscrobbler 1.2.1 protocol.
Peachnote is quite an innovative approach to music analysis. Developed by Vladimir Viro, a renaissance man who bridges the worlds of classical music and advanced mathematics, the Peachnote API provides the ability to search a large collection of public compositions by melody or sequence of chords.
For music enthusiasts who thrive on insider knowledge and detailed music conversation, WhoSampled would be just their cup of tea. It's basically an online community for discovering and discussing sampled music, remixes and cover songs. WhoSampled has partnered with The Echo Nest to provide the WhoSampled API that allows developers to access and integrate its functionality with other applications.
Two days, a room full of hackers and one theme: music. This is the premise behind the Stockholm Music Hack Day, which resulted in 31 projects including hardware hacks, mobile, web and desktop applications. A number of the web applications are live and available for anyone to use.