Since I intend to do a lot of fiddling with Arduinos, and because I need the soldering practice, I bought the breadboard voltage regulator kit (by Solarbotics) from Makershed. The kit is simple – it just requires the soldering of a handful of parts to the provided board. The instructions are super-clear, so even though I barely know what the parts are and only recently discovered that LEDs have to be connected in a certain direction, the task was easy. I did find, however, that I still totally suck at soldering, even after the purchase of a nicer iron. With time perhaps.
In the end, though it took me probably 5 minutes to solder each joint, I plugged the thing in and it works! This regulator is supposed to hold the voltage at 5V, which is perfect for the Arduino since that is what it outputs. Pretty handy little thing, and if you are a bit more knowledgeable you could make your own from scratch for way cheaper.