The first spider is from the family Tetragnathidae, probably a Phonognatha graeffei (leaf curling spider), or one of the other three species in that genus found in Australia.
The 2nd spider is of course the redback spider.
Identifying spiders is a very difficult process for a number of reasons,
1. They are small (many spiders are smaller than a pin head fully grown)
2. The best spider identification guide can only identify spiders down to Subfamily (not species)