Yes you read it right. Most of the Android phones allow you to charge your other USB devices, this is possible with the USB host feature on a lot of Android devices along with a MicroUSB to USB connector you find easily in the market.
We recently displayed how you can charge your iPhone with an Onion and got an overwhelming response from people about how fascinated they were to see it actually work!
We also showcased how you could easily connect your USB accessories to your Android devices, the USB OTG (USB On-The-Go) enables the Android device to act as a host allowing a USB flash drive, mouse, or keyboard to be attached and connecting USB peripherals directly for communication purposes among them.
We don’t wish to get in to more technical details about how this works but want to show you an image by one of our friends, Aditya Pandya, @laemo in Twitter
image courtesy: @laemo on Twitter
As you can see an iPhone 4S is being magically charged via the Galaxy Nexus using the iPhone USB cable and the USB OTG cable connected to the Galaxy Nexus.
Though the charging is slow, it is, nevertheless.
We recommend everyone to go buy this piece of hardware, the USB OTG Cable, you could do a hell lot with it.