Best tips that I have from experiece:
a) For phone - use Skype to make calls (see below) - though I also have a UK Orange sim for use while there - and also works out cheaper, of course, than using my AU phone to call home. Don't forget to divert your Aussie number to message bank - that way you don't pay for all those long-distance calls yourself when someone rings you.
b) for internet -often find I have use of system in places where I stay - but if you don't want to beusing your internet all day every day: try using the free WiFi spots, like MacDonalds. Many hotels charge exhorbitant rates - pity they haven't worked out (like their Aussie cousins) that a free service is what is expected of business class hotels, at least.
I am sure others have a lot of other suggestions to make - but these are good, cheap ones: depends, of course, on your useage and needs.