I (well Ed) had nothing but problems getting mine off because the screws had seized on them. Get as much WD40 on to it as you can and let it soak. Only advice i can give. Be careful taking them off also, as the can chew very easily.
Very easy, as long as you are careful with the screws that hold it down, you will need to slacken them very progressively otherwise you can end up rounding the heads and then you will have to dremel them off and get new ones
It is best to leave it 20-30 minutes to allow most of the oil to drain back intothe sump, just watch for crap getting inside yourengine when you do it...