Not really. When your AC is not turned on the AC belt is not spinning anything because the clutch is not engaged yet on the compressor. The pulley just freely spins on the compressor until the AC is turned on then the AC system will engage the clutch on the compressor pulley and then the AC belt powers your AC system. This is why you notice a slight drop in RPM when you engage the AC.

The PS system is always on. Whether you are sitting at a light, driving straight on the highway, or taking a trip on some twisty, country backroads the PS pump is always being used and exerts a constant drain on the engine. The same is also true of the alternator...however you need the alternator to run the engine and unless you go with an electric one you are going to be keeping the alternator belt on.

Turning the wheel without PS sucks when you are sitting still...however it is pretty easy to do even when driving at a slow pace.