Things you will need:
a 120VAC to 9VDC adapter, mine was also rated for 800mA - around $20 @ Radio Shack
Solder and Soldering Iron
Some 22 gauge wire
I used a "M" connector between my adapter and controller but you can use whatever you want or hard wire it, doesn't matter.
WARNING: DO NOT HAVE BATTERIES INSTALLED IN THE CONTROLLER AND PLUG IT IN TO THE WALL AT THE SAME TIME!!!
Eventually I would like to figure out how I could have the batteries installed and just plug it in to charge the helicopter. Perhaps a small power select switch would do the trick?