Hi Marc,
It's a timely post for those in Sydney, and visitors, as lots has changed, yes.
http://www.sca.nsw.gov.au/recreation/warragamba-dam/FAQ
I recall tours inside the dam structure, as they do at Hoover Dam in the USA. These have been stopped for security reasons. I heard a story that the lower parts of the wall inside are now flooded and inaccessible, but I don't know for sure. Anyone know?
You can picnic there, but there is no kiosk serving a good latte
Cheers