I think the Power supply should be fine, Australia is 230V, 50Hz, same as in most of Europe - with the exception of a few countries in the Balkans (Croatia, Bosnia, Serbia, Albania, etc). Since you've already got a PAL console, any games you buy in Europe
will work fine on your console as long as you're not traveling to France. France is SECAM and I don't believe PAL based games will play on French consoles. or vice-versa.
I would double check about the power issue though, I don't want to be blamed for damaging your console!
You will still be able to use your current Gamertag, but you won't be able to buy points for it as points are region specific.