Excellent captures Waspo!
These clouds are called 'Mammatus' (pronounced mamartus). They are often associated with severe weather, but they, themselves, do not produce the severe weather! They are usually found on the underside of a thunderstorm anvil, but can often appear with other cloud formations as well! They are often quite short-lived, and are usually the favourite cloud formations of storm chasers and weather freaks!!
This was one of the better displays I have seen in Melbourne, and the best were around 5pm last night while I, unfortunately, was cameraless.
I did manage to capture this one as they were almost disappearing earlier in the day.
You have done extremely well to capture these Waspo! Well done!
<sorry if that was too technical....just thought I'd explain what they were for those interested!>