And provided the lead for your iPad 1 power charger doesn't terminate in the bonkers proprietary iConnector. If it's a microUSB that inserts into the iConnector then you'll be ok.
The ipad chargers (well the ipad 2 at least) is a plug with a standard usb port on it. You can detach the cable and charge any old usb thinger
Well to be fair, even though it ends in a standard USB connection, it still ignores the USB standard for identifying itself as a high powered port. USB standard states that a high powered USB port is identified by jumpering the data pins (some sources say you need to put a resistor between the pins). Apple, in order to claim a proprietary design and charge licensing fees to any company wanting to make a charger for their devices, does this by using a series of resistors on the power lines.
I recently bought a car adapter that took a car charger port and gives two usb ports. In order to get it to provide anything other than 100 mA I had to crack it open and solder the data pins together. I'll be interested to see if the r-pi also has this issue, or if it was more a problem of my phone being too intelligent just to automatically take the power it needed.
Dear forum: Play nice