VMware vCenter Server Heartbeat was announced at VMworld Europe 2009 and is now available for customers. vCenter Heartbeat provides protection for vCenter Server 2.5:

• Protect VMware vCenter Server and its database against hardware, OS, application and network downtime.
• Ensure seamless failover and failback of VMware vCenter Server.
• Provide reliable disaster recovery for VMware vCenter Server in local and remote locations.

Listprice for vCenter Heartbeat is $12,093.95 with 1 year gold support.

Check the release notes for more info.