Second time lucky. The first portable battery charger i bought for the iPhone 3g turned out to be a lemon. It sucked. Could hardly hold a charge. That lucky australian somehow got his to work, but mine is a piece of junk. So, in it goes to the junk draw for the next 14 years.
In the meantime, however, I’ve just purchased THIS!

It’s a small device charger (not just for iPhone, but most mobile phones, game toys, etc – runs out 5v). It’s made by XPAL and is called XP2000. It fully charges in about 4 hours and can recharge your iPhone (1st gen, 2nd gen – and i’d say 3rd gen) – as long as you use your iPod cable (USB to iPod jack). Great for traveling or if you DO have an iPhone, great for keeping in your bag in case your iPhone runs out of batteries, like it does every GOD DAMN HOURZZRSZZZZOOOHHH-I’M-MAD!!! lol?
But it is lovely and does just what it says. Nice.