Does anyone know what those valves are/do in my picture?http://img223.imageshack.us/my.php?image=dsc00531it9.jpg
They are shut off valves to the faucet for servicing. They allow you to pull the cartridge out and replace it.
To me that is a water mixing valve used in showers, you can see the plug on the top, so when the face plate is attached the tap tops are fitted to either side of the spout.
Those are the hot and cold water pipes. You can turn off the water to the handle/knob by adjusting these valves. Although, it may be simpler and quicker to simply turn off the main for the home. This link has some similar examples and dialogue.
I'm a licensed Plumber and this is what those are for....if you doubt me contact Delta and speak with their customer service reps... Those are Isolation valves that plumbers use to turn off the water to you shower to make repairs within the shower valve its self (O rings...mixing cartridge, etc).....otherwise the water would have to be shut off to the whole house when making a repair. That and if you look closely they are NOT part of the valve its self....the look like valves that are attached (Threaded) to the Hot Cold inlets on the valve. My first guess...that is a Delta, Monitor, Shower Valve. Maybe a Moen positemp...but I'm pretty sure its a Monitor Series Delta valve. They're are BOTH very similar.
I have seen this type of valve when it is installed in a location that makes no wet wall access from the back side , one can also adjust the temp a preset safety so one won't get scalded from hot water
