If you want to do it on your own, you need to know that you shouldn't send your mortgage company a check of half of monthly payment once every two weeks. Instead, you should pay a bit more in your monthly check.

You cannot simply mail in half a payment every two weeks to your mortgage lender. Since they do not accept partial payments for legal and accounting reasons, the mortgage company would just mail your half-payment back to you.

Instead, the bi-weekly mortgage company is an intermediary between you and your mortgage lender. They automatically debit your checking account every two weeks for half of your mortgage payment, then place your funds into a trust account. Basically, this is just a holding account for your money. In another two weeks, there is another automatic deduction from your checking account, and so on. When your mortgage payment is due, your funds are withdrawn from the trust account and forwarded to your mortgage lender.

Since you are placing funds into the trust account faster than your mortgage payments are due, you eventually accumulate enough money to make an "extra" payment. The way the cycle works, this occurs once a year. The extra payment is applied directly to your principal balance, which causes your loan to amortize faster, pay off more quickly and save you thousands of dollars.