^^^ Hahahahaha, that's pretty funny coming from a Kiwi!

Wow.... mention Australia and all you guys can do is cry about how scared you are of the bloody insects here!
Stop being such wusses, you big girls. We have fly spray and other insecticides in this country... funnily enough... they work!
I get redback spiders at my house sometimes.... They're bigger than average spiders and the big red stripe suggests that they might be deadly... so just stay away from them or unleash chemical warfare on the area from which they came from. If you keep up a fairly regular insecticide surface spray around your windows, doors and other openings you will not have a problem with 'deadly' creatures.
The beaches are always clearly signed when dangerous jellyfish and sharks are around. If you take Tronksi's advice and always swim between the flags at beaches with lifeguards no harm will come to you. I did surf lifesaving when I was a kid... was at the beach all the time... never had a problem. Don't be like all the damn fool tourists who ignore the flags... our beaches are dangerous. The flags denote the safest area of the beach in which to swim and help the life guards keep a track on you. If you get in trouble, stay calm, tread water and raise your arm. Help will come swiftly.
Australians don't have a problem with Americans.... as long as they aren't loud-mouthed, obnoxious bananas.... and many are. I find it worst when a group of Americans travel together... they seem to encourage each other to make a scene of themselves and talk absolute rubbish. Having said that, I doubt many people will give you a serious hard time about being a yank if you're a good kid. If you're a knob jockey then you may have issues... but that will be to do with being a knob.
Someone already said this too... learn to take a joke and also understand that you will be called 'mate' by everyone from your best friends to complete strangers.
Australia is typically a pretty laid back place, especially the Gold Coast.... Not the best place in the country to live but one of the best for a holiday.
Also, as you'll be playing AH in a completely different time zone you should try looking up some of the Aussie and Kiwi players.... good bunch of guys and I'm sure the Raw Prawns wouldn't mind you flying with us.... provided your voice isn't at a pitch that will make us cringe and you don't talk relentless crap like most other kids...
We fly Rooks and you'll recognise our accents immediately... it sticks out like dogs' balls when there are yanks on with us.
Australia is a good place... just don't forget your sunscreen.