Following in the footsteps of Facebook, which opened up its social network to developers about a year ago, MySpace is now launching its own developer platform (in a beta version), and it already features an application gallery for users. This can't really be described as a huge open source event--it's more akin to MySpace widgetizing--but it is built on open protocols and is already leading to freely available new applications. Stacey Higginbotham has a full report and screenshots at GigaOm.com.