Just wanted to share my understanding of things. I believe one usb port from any managed device (ie, computer, usb hub, pineapple usb port, etc) is designed to give 500ma of power (but I have read there are exceptions). Also the AWUS036NHA is capable of outputting 1000mw of power to it's wifi radio. This means it could actually use a little more than that due to the power requirements of the internal components.
A nifty equation can convert the power ouput (mw) to the required amps (ma in this case). The equation is Watts/Volts=Amps. So in this example we have 1 Watt (1000mw) / 5 Volts (usb voltage) = 0.25 Amps or 250ma.
Hopefully this can help some of you when you are trying to figure up what the power requirements will be when setting up your pineapples.
Best of luck to everyone!