Stacy Millions built his mintyboost to match up with a OpenMoko Neo phone. By default, the phone uses the ‘correct’ 100mA drain current to charge when there is no USB enumeration. However, it is possible to force the phone into using a 500mA charging current via software. So he wrote a little app that will hypercharge!
This is pretty cool: if you have a typical phone, there is no way to poke & hack the hardware at these levels.
MintyBoost USB Charger Kit v1.2 – Build your own MintyBoost: a small & simple (but very powerful and very MAKE-like)USB charger for your iPod (or other mp3 player), camera, cell phone, and any other gadget you can plug into a USB port to charge.