If you have a conventional mortgage, every penny you pay on your mortgage over your minimum payment is applied directly to the principle. Whether this is the best financial move for you or not depends on many factors. Do you have other debt? Mortgage debt is usually tax deductable, so most advisors would suggest you pay off credit cards, auto loans or other debt before your mortgage.
Do you have a savings account with sufficient reserves set aside in case you get sick or lose your job? Once you apply the additional money to your mortgage, it's gone. If you have several months of savings available and other debt paid off, directing additional funds to your mortgage can be a good idea.
I hope this helps.