Forms Question

on asking for a phone number

[Matrixster]

In forms, when you are asking the users to input a phone number, what is best to use:
one text box
Two text boxes (one for area code)
or three text boxes?

[txbakers]

for me it depends on the usage. If it's just going to display back to them, I use one box. If it's critical that I have three separate fields and accurate input, I"ll use three boxes.

I've never used two, since phone configuration is different all over the world.