store.apple.com/us/product/TV652ZM/A

Enrika,
I own this one (link above) and it's great.
I ordered it right online from the apple store and it continues to work just fine even since my upgrade to 3.0

Bruce

There is a difference between the original iPhone and the g2 g3 iPhones (3G/3GS). The original iPhone allowed for USB or FireWire docking. The 3G and 3GS do not allow for FireWire docking. Some accessories do FireWire docking because the very first iPods only did FireWire docking.

It's tough because no vendor is going to say what pins it's using on the 30-pin iPod connector because it's too much information. So instead look for 3G compatibility...but again, some feel that's even too much information, even though it may make a critical difference.

You'll see if your external battery/charger or whatever is actually working because the battery icon will show a plugged in or charging icon...plus of course you'll be able to run longer. If you have the original iPhone and are having this problem, then it's a problem with your iPhone or the battery pack not working.

There is an adapter that converts from FireWire to USB:
Scosche Charging Adapter $25
www.amazon.com/Scosche-Ch.../ref=sr_1_1

I have this and use it on my boat all the time.

As far as other batteries...there are a bunch, you might want to search around. The there are a couple of things to look for:
1) Compatibility with 3G
2) mAh (milliwatt amp hours). You want a big number here. I believe the built-in battery is 1400mAh. This battery, which I have and it works well with the 3G, is 1900mAh and sells for $17:
www.handhelditems.com/1900mah...311.html

Next, you're going to want to look at the features of the battery. For example, does it use a standard iPod dock connecter to charge the battery (this one does), or does it use mini-USB (which would be a pain because you'd need to carry yet another cable).

Other features include the ability to hook the battery up to the iPhone and plug the battery in and having the charger charge both the battery and the iPhone the above mentioned battery doesn't, but I believe the Richard Solo $49 does:
richardsolo.com/index.asp
The Richard Solo battery unfortunately is only 1800mAh, costs a lot more, and uses a damn mini-usb to charge the battery.

There are also battery cases, like the Morphie Juice pack:
www.mophie.com/SearchResults.asp
I think these are fucking retarded because if it's a case, it should fucking protect the iPhone, and not leave much of it exposed...though if you use your iPhone without protection anyway, this could be a good battery...just to come crying to me when you drop your iPhone!

And this one is so close to perfection that it makes me cry because the only flaw is a total deal breaker:
fastmac.com/iv.php
It comes with 3100mAh...My penis grows 2 inches just saying that!
It includes a LED light for use as flash light and photos.
It has a USB port to charge multiple devices.
It's $79...not bad considering.
The critical flaw...although it's a case, it doesn't protect the whole unit, and you can't use another case with it. Grrr...

Anyway, did I mention something about too much information in this post?

Did I even answer your question?

I get that error message frequently, even when using accessories that CAME WITH the iPhone, such as its charging cradle!

Daring Fireball did a comparison of a couple rechargeable battery packs for the iPhone:

daringfireball.net/2008/10/...o_battery