Conexus has just announced that they’ll be selling the Mophie Juicepack Air iPhone case in Australia. Considering it apparently doubles the battery life of the 3GS without adding too much bulk, this is great news for iPhone owners.

The case will set you back $130, but the addition of the 1200mAH battery will extend talk time to 4.5 hours over 3G, audio playback to 27 hours and video playback to 9 hours. You’ll also get up to 8 hours internet browsing time on Wi-Fi.

Of course, all those figures will be lower in real world testing, but it does sound like a pretty good boost to the iPhone’s relatively poor battery performance.

[Conexus]