From the release notes:
Use Control and Command-Click to support multi-button mouse: VMware Fusion now supports Control-Click to send a right mouse click and Command-Click to send a middle mouse click to your virtual machines.
You can disable OS keyboard and mouse shortcuts separately in VMware Fusion > Preferences so all keyboard and mouse input goes directly to the virtual machine.
OK... I read that but its meaning didn't really sink in. I only do dev work with an external keyboard and mouse, so passing all mouse events to the VM makes sense.
I also disabled some Exposé keys since I don't use most of them, but being able to bring up Dashboard within the VM is pretty slick.