I found one on Australian natives but it's geared more towards someone with a bit of subject knowledge already here's the link:
http://www.anbg.gov.au/index.html
here is another but it's more about Queensland though:
http://members.ozemail.com.au/~peterrjones/plants.html
This site is linked to a nursery but still useful:
http://www.australiaplants.com/au_plants_a-b-c.htm

Thank you for these ID sites, especially the Hainault Forest one.

