Hello!
I am citizen of India and recently I have submitted an Application for the L'Arche mobile Community which works for the disabled people. They are paying me 675$ per month with boarding and lodging. They will also help me in getting B1 Visa. I am curious to know will USA cut off taxes from the salary I receive per month? If yes How much they will deduct from my monthly salary? Will I have to pay this taxes every month or once in a year?

B-1 (or always issued as B-1/B-2) is a non-immigrant visa known as visitor's visa. With this visa, you are not allowed to work or go to school, etc.

If job offer you had states that you must enter US on B-1, do not take it...

The "B" Visitor Visa is a non-immigrant visa for persons desiring to enter the United States temporarily for business (B-1) or temporarily for pleasure (B-2). Read Your U.S. Tax Return: The U.S. Visas (http://taxipay.blogspot.com/2008/08/us-visas.html)

To answer your tax question, you have not provided enough information.

How long is your stay?

Will the room and board be considered taxable compensation?