It was hinted that Microsoft might release the beta at the Microsoft Management Summit next week: "He said the VMM version that will support Hyper-V will ship with the hypervisor add-on for Windows Server 2008. He said the timeframe for that release will be June or July. He hinted that the beta of VMM that supports Hyper-V would be released next week at Microsoft's Management Summit in Las Vegas. In addition, he disclosed that Microsoft has 4.5 million seats of Microsoft Application Virtualization (SoftGrid) out in the field. He said Kidaro, which Microsoft acquired in March, would become an important tool for managing virtual PCs."

Source: Networkworld.