Vietnam Country Guide

I'm trying to decide where to go P'pines of Vietnam for a month very budget backpacking. I've never been to either before. Anybody help me with making a decision. Seems flights to/fro Aus are about the same.

3G Iphone from Singapore, of course without contract. Just checked with Singtel that they only sell Iphones with contracts. Anyone can advise beside Singtel, where in Singapore can I find reliable shops to buy Iphone without contract? And he is from Vietnam, is there anything that he need to take note when using the Iphone? Worldwide warranty perhaps? Any advice most appreciated! Thanks all!!

I am traveling to the Philippines from Hanoi, and I have an extra piece of luggage with me. The VN website says I am allowed only one piece of luggage. How much will the extra piece of luggage cost me? I dont think the extra piece weighs more than 20kg (the allowed weight per piece of luggage). Thanks!