Healthbase Australia has updated the online Australian Medicines Terminology browser to include the 2.20 version of the AMT released by NEHTA a few days ago.
All deprecated versions are still available for browsing/searching.
Pity the download process still cannot be automated. Perhaps if this were the 1980s NEHTA could publish the updates (with sensible filenames!) via an FTP server. I guess we have a lot of catching up to do! Maybe we will just have to keep waiting another couple of years until a cumbersome Web service is established?