For future reference, VMware releases always seem to come in bunches. Update 6 for vCenter 2.5 has been released and can be downloaded here.
The update mostly includes guest operating system custimization enhancements.
Here’s the what’s new section from the release notes:
Guest Operating Systems Customization Improvements
Customization support for the following guest operating systems has been added in this release:
For more complete information about supported guests included in this release, see the VMware Compatibility Guide.
Windows 7 Enterprise (32-bit and 64-bit)
Windows 7 Ultimate (32-bit and 64-bit)
Windows 7 Professional (32-bit and 64-bit)
Windows 7 Home Premium (32-bit and 64-bit)
Windows Server 2008 R2 Standard Edition (64-bit)
Windows Server 2008 R2 Enterprise Edition (64-bit)
Windows Server 2008 R2 Datacenter Edition (64-bit)
Windows Server 2008 R2 Web Server (64-bit)
Support for Firefox 3.x Browsers with VirtualCenter Web Access
This release adds support for Firefox 3.x browsers with VirtualCenter Web Access. Firefox 3.x is not a supported browser for ESX Server 3.5 Update 5 Web Access with this release.