Buy a SIM card over there to make calls and log into your Telstra voicemail.
Otherwise telstra will scarew you with a juicy bill when you get home.

Good advice. The reason I wanted to take my iPhone is so I can use the iPod facility and contacts for sending emails etc. But I take your point - time to dust off my old iPod nano (first generation 2GB - will have to be selective with my song choice!)

i brought my iPhone and Razr overseas. iPhone - internet, mail, IM. The Razr is a backup. I only use public internet cafes if i have no option, otherwise i dont like using their keyboards & mouse. I also use the local SIM of the country i go to. My last trip was not being aware that I have to edit APN settings to access the net so I missed out that feature a whole lot.

If I can get tethering (& 3G) to work overseas next time, then all i really need is a 3G signal and use my laptop in the comforts of my hotel room.

I took my iphone to China with me a few months ago and it was the best decision I made. Disable 3G through your settings to avoid accidently using it and getting huge bills. You can still use your wireless internet in cafes / hotels / airports for free internet while you're travelling. It's amazing how many places you can pick up wireless. I used my ipod app constantly and my library plus games when I was bored on planes and trains. I'd definately recommend that you take it. As for phone calls, it depends how long you're going for but you probably won't need to make a call. Use a public phone and prepaid card to keep costs low.