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.
Rumblefish, champion of what is good and just and legally musical, will help you change your tune for the better. This company has produced a music licensing API so that you can add copyrighted songs to your YouTube videos. Of course the concept can be applied more widely and liberally. Rumblefish has even devised custom license ‘portals’ that present licensing options based on the intended use of the music. This implies that the agreement and cost of licensing a track could be more expensive depending on where and how it is used.