Opera Software today released the first beta version of its flagship browser that uses the open-source WebKit rendering engine, making good on a pledge from February. "Opera Next" -- analogous to a beta -- shipped Tuesday for Windows and OS X as version 15, skipping from the current production-grade browser, Opera 12, to synchronize with the engine's identifier. The application identifies itself as a WebKit browser, the same engine used by Apple's Safari and Google's Chrome.