I can't comment on the veracity of Telstra's speed claims, but Optus' are a complete joke. Most of the time I'm lucky to get even modem level speeds out of my 3G card, let alone 3.2Mbps. Once again, the schpiel quotes the theoretical maximum and conveniently ignores reality.
I'm not sure how relevant these speeds are going to be for several years - except maybe to keeping shaming the U.S. into making just the basic steps toward even adequate broadband a reality for its masses.