Is your iPhone battery draining before you're done with all your talking and surfing and jamming and video watching? You can double its power with a Mophie Juice Pack, and I've got one to give away.

Made to slide snugly right over your iPhone, the Juice Pack has a soft, rubberized finish to give you a better grip on things, and weights just 3 ounces. It comes fully charged right out of the box and will give you up to 250 additional hours of standby time, 24 hours of audio playback, 7 hours of video playback and 8 hours of talk time. For you web and email junkies, you'll get up to another 6 hours of Internet use.

The first external iPhone battery certified by Apple, it's designed to deplete itself first, so when it's done just slide it off and your iPhone will still be fully charged.

They run $99.95, but this week I'm going to let one of you score one for free. Just enter your email address here, and on Friday, May 9th, I'll pick one of you at random. You can send me an email from your iPhone to thank me.

Enter to win a Mophie Juice Pack