No, the governor *is* the clock/power-down algorithm. It's all in the software (kernel). You can switch between fastest power-up (responsiveness), fastest power-down (battery), different load sampling/detection algorithms (look up, for example, the recent "smartass" governor), etc. with SetCPU or a similar tool.
Android is quite good at hitting low-power/sleep states when it's not doing anything/much. It's just that the free multitasking, background-updating widgets, and the stuff you get with an open sandbox can prevent the chip from idling enough for these low-power states.
On the other end, the underclock to 800mhz (eliminating the 1000mhz CPU state) prevents the iPhone from draining as fast under full load. You can manually simulate this on Android too, of course, and though you may not hit iPhone4 battery times (depending on phone/apps/widgets/use) it makes a really noticeable difference.