Power Converter

1 have 3 battery operated LED lights that I would like to run on a single AC power converter?

Each light runs on 3 AAA batteries.
My question is can I buy one AC to DC converter to run all 3?
If it I use only 1 converter how should I wire it?
What amp rating do I need?

You have not provided quite enough information to completely answer your questions, but here it goes...

Three AAA's are about 4.5 Volts. Most LED's function across a range of currents from about 1 milliAmp to about 10 milliAmps (brightness increasing with increasing current) and have not too much increase in voltage across this range. That means that you will need some sort of current limiting device to prevent buring them up. That being the case, you could go for a 6V DC source capable of delivering 100mA of current (these are quite common) and put a variable resistor in series with it (also called a potentiometer or rheostat) of about 10 kilo-Ohms. You could then connect the LED's in parallel to the resistor and vary the brightness by varying the resistance.

If, on the other hand, you were looking to turn these on one at a time, you might explore using a 12 volt source with the same variable resistor and placing the LED's in series. By placing a 1 kOhm resistor in parallel with the top 2 LED's, you can get them to turn on one at a time.

I Was Going to Toshi Station to Pick Up Some Power Converter