When you pay weekly or bi weekly you pay the exact same amount as you would monthly,only it's split up in 4 payments. Say you have a 1000 dollar a month mortgage,first you have to pay the monthly payment of 1000 dollars,then you must pay 250 dollars for the first weekly payment so the first month you do this can be tough as you end up making 2 payments that month but once past that it's just 250 per week.
The key to this is how the bank charges interest on the loan,now as a US citizen you may have tax benefits from the interest paid so I would consult an accountant to be sure you get the best benefits. In Canada we cant deduct the interest paid so it's in our best interest..pun intended... to pay off the mortgage asap!
As I said I brought the amortization term down from 25 years to 13 so I saved 12 years of payments,you only pay a small amount on the prime, about 90% of each payment is just the interest calculated on the loan over the amortization length.
A 100,000 dollar home will cost over 300,000 in payment over a 20 year term!this is at about 5% give or take.