A new Beta build of the next iteration of Windows Live Messenger has been leaked and is available for download. Windows Live Messenger 9.0 initially debuted into Beta at the end of 2007, alongside the final release of version 8.5. Back in November of the past year, Microsoft's limited Windows Live Messenger 9.0 Beta grew to unexpected proportions as the bits for the instant messaging client were leaked and made available for download from third-party sources. Almost nine months later, the B...