You don't need to move to Australia. I opened an Australian bank account precisely for this purpose. All I had to do was travel to their branch in London to identify myself.

Apart from high interest rates, there are other advantages to AUD: low government debt, and a commodity-rich country that is likely to thrive if things get tough for the world.

I also bought AUD from USD when it was 10% undervalued according to PPP, so that's already a 40% gain in USD terms:

http://fx.sauder.ubc.ca/PPP.html

What are your tax rates on interest?