I know that there is the Defence Weapons Research Facility just out side of Adelaide, in South Australia (my dad used to work there), but I've been wondering does australia have any 'known' bases like Area 51?

Well since area 51 is a place where they test new planes, most likly there would be a place in australia that has a guarded peice of land designated for testing new aircraft.

Just google austrial air force bases.

Yep Pine Gap. It's not for airforce though, and it's part of the Echelon network. (I think).

Actually koji_k Pine Gap is a joint American/Australian base.

Run by the NSA, as a signals intercept station.