When we went I got a Telstra prepaid quadband phone cheap ($99.00) unlocked it $50.00 and put one of vroam's sim cards in it worked in the UK and Italy.http://www.vroam.com/
and you can top it up. You get your own phone number, it seemed to work quite well.
We leased a peugeot through http://www.drivetravel.com/
who are actually based in Australia, okay its Victoria. It worked out really well. Car was brand new, roadside assist was covered, insurance was covered and it was under warranty. At the end we just dropped it back at Malpensa. NB there are charges for picking up and dropping off outside of France.
Re having money over there, yes I took for immediate needs in GBP and a small amount of Euro, we had Visa but I also went to the NAB, who we bank with and got http://www.nab.com.au/wps/wcm/connec..._finance/1/5/5
and loaded it up with Euro which was good cos you paid up front, the exchange rate was set and you can take money out of ATM's anywhere just as you do at home. I think the ANZ also does the same kind of thing - can't know who you bank with
Re postage - we sent some stuff home from the Isle of Mann that we wouldn't need in Italy - was horrendously expensive and bear in mind Germany doesn't appear to have parcel post they seem to use DHL (ebay experiences) which makes it even more expensive.
Yes alcohol seemed very expensive, but then again they didn't seem to measure spirits the same way we do. Also, sitting down at a bar to have a drink can be very expensive, Venice - horrendously so, I think I also asked the jazz band to play something and that was just a stupid thing to do as that got added to the bill too - although I will always remember it.
For some accommodation I used this guy's website, or books - has stuff to suit most budgets http://www.sawdays.co.uk/
that is about all I can think of at present.