You can do this yourself and avoid paying the associated fees. Just pay one half of a payment extra every six months. Same thing, no fees.

You end up making one extra pmt. a year which can save you thousands in interest costs over the life of your loan & allow you to pay it off quicker

Instead of making 12 monthly payments, you are making 13 payments a year. Basically instead of making each payment on the 1st, you would have 1/2 due payment made every two weeks. Giving you 1 extra payment to the bank each year. You can also add more to your payment, given your lender allows, to pay down your loan faster. Bi weekly is used to accelerate your payoff.

Instead of making 12 monthly payments, you are making 13 payments a year. Basically instead of making each payment on the 1st, you would have 1/2 due payment made every two weeks. Giving you 1 extra payment to the bank each year. You can also add more to your payment, given your lender allows, to pay down your loan faster. Bi weekly is used to accelerate your payoff

As esexton said, save the fees and do it yourself. An alternative is to increase your regular payment by at least 1/12th of your regular payment - that is a bit easier than trying to save up an extra full payment. With a fixed-rate loan this will speed up how fast your mortgage is paid but not change your minimum payment. You may request a "recast" if you want to pay down your balance by a large sum and that would reduce your payment. Most conventional mortgages have no prepayment penalty.