Today at the TechCrunch Disrupt conference in New York, Twitter cofounder Jack Dorsey demonstrated Square, his latest startup whose service allows users to accept credit-card payments on iPhone and Android devices.

The demo didn’t show us anything that we haven’t seen before from Square, but Dorsey showed how Square could be specifically useful for charitable organizations. He managed to goad TechCrunch’s Michael Arrington into donating $100 to Charity Water — a nonprofit dedicated to bringing clean water to developing nations — during his presentation.

Towards the end of the session, Arrington pushed things even further: He asked if anyone in the audience would be willing to donate $1,000 to Charity Water. Jason Calacanis, the CEO of Mahalo and Arrington’s former partner for the TechCrunch 50 conference, was the first to accept. Arrington proceeded to guilt Google developer evangelist Don Dodge into donating $1,000 as well.

All of this happened in a matter of a few minutes, and it goes to show just how much Square may shift the way handle quick financial transactions in our daily lives. Of course, it will be useful for small businesses, flea markets, and farmers markets — but just like how the Red Cross used a simple text method for donating money to Haiti, Square will also remove much of the difficulty in donating money to charities.

You can check out a video of the entire session, along with Dorsey’s donation hustle, below:

http://cdn.livestream.com/grid/LSPlayer.swf?channel=disrupt&clip=pla_1fe471d3-7026-4f50-ba22-7dca70ae4701&autoPlay=false

Watch live streaming video from disrupt at livestream.com

[Image and video via TechCrunch]