Ran across the utility RVTools today. It’s a small application which uses the Virtual Infrastructure SDK to display the installed version of VM Tools and lets you if it’s upgradable.
Within the RVTools GUI, you can select and upgrade multiple hosts by clicking “Upgrade VMware Tools”. Within VirtualCenter, you’ll see an Upgrade VMware Tools task for each VM selected.
RVTools works with ESX 3.x and VirtualCenter 2.x and can be found at http://rvtools.deveij.com/