Aussie Transformer Prime owners, if you've been hanging out for Android 4.1, also known as "Jelly Bean", it looks like the update was pushed through yesterday evening, so there's nothing stopping you from installing the new version on the Tegra 3-powered tablet.
Ausdroid was tipped off to the news late last night. Comments on the story suggest that some users were having trouble grabbing the update, probably due to traffic, but things might be better this morning as the initial rush has died down (you'd hope).
To see if you can update, just browse to "Settings", then "Check for Update". If you're experiencing difficulties with the update not appearing, Ausdroid commenter "Sandman_Rides" recommends the following steps:
If you get the no update available, try this. Go to settings- apps- all- DMClient- clicked clear cache AND force stop... restarted the tablet and check system update again and you should be right. Worked for me.
If you do grab the update, let us know how you go!