CANNES/HELSINKI (Reuters) - The world's largest mobile phone maker, Nokia, and software giant Microsoft struck a deal on Monday to make it easier for consumers to buy digital music on-line and play it back on their handsets. In a comprehensive agreement, which involves a separate deal with digital media company Loudeye, Nokia agreed to put Microsoft's music player software into its handsets. In return, Microsoft, will introduce open standards for digital music compression and piracy protection in its Media Players for personal computers. "Users can synchronize their music collection with their mobile device," Nokia said in a statement. "This agreement...