The trouble with some music sites and APIs on the web is that they have been known to get taken down due to legal battles. Worse yet, often the only real way to monetize is to take a teensy percentage of an already low-priced track. BandsInTown wants to help your music site stay up and even make money.
The Punkrock.org API uses POST and GET calls that allow a user of your app to access their own user info on Punkrock.org, including friends, mail, notifications and allows them to upload photos. Requesting an API key is required for access to services.
The Take.io API from Brazil has a REST protocol with data formats in XML and JSON. According to Take.net, "The take.io RESTful API currently defines five services: SSO, Core, Billing, Messages and Reports." The company states further that, "Take.io is Take.net DNA translated into a set of APIs designed to allow companies to use SMS, MMS, voice, pricing, location, CRM, etc., all of which are integrated with their existing systems."