My gut tells me that it won't help to pay two weeks early. I think adding principal to payments is the way to go.
Many companies offer the bi-weekly payments, but they CHARGE you for that. So...I would tend to think that paying early will not necessarily increase your principal payments. I believe the prinicpal payment for a given month is set, regardless of what day you pay it.
I would call to check too. Otherwise, you might as well earn extra interest on the money by keeping it in your ING or savings account an extra two weeks! Even $1,000 at 3% earns $2.50 per month, or $1.25 every two weeks. So...if your mortage company isn't giving you any credit for it, at least get something from the bank!
