No, they didn't. But somebody seems to have been awfully successful at convincing Americans that they did! This issue constantly comes up on FR - almost everytime there is a thread concerning Australia in any way.
Guns are not banned in Australia - not even close. A law abiding citizen can own just about any type of firearm if they are willing to do the necessary paperwork to get the licence they need. This really isn't that difficult - just a bit time consuming for higher level licences. It's actually very easy for a basic licence - pretty much just a criminal record check to make sure you haven't been convicted of a crime in the last ten years (and have never been convicted of certain violent crimes).
Our gun laws aren't particularly good ones - but they're really not that bad. If you want to own guns, then as long as there's no reason you shouldn't (like criminal convictions) you can.
Thank you again for clearing that up and FReegards....
Here's a thread that may be the root of the gun banning misinformation:
Crossbows, samurai swords to be banned (in Australia)
http://www.freerepublic.com/focus/f-news/966297/posts
But, a key point - can you practically use them for self-defense in your home? Without a ruinous prosecution afterwards?