Bi-weekly means your making 26 payments (there's 52 weeks per year), which isn't the same thing as bi-monthly (which means there 24 payments).
Hence, your "accelerated" mortage pay off from a bi-weekly plan would be no different than if you just made 1 extra monthly payment toward your principle each year…except that companies that administer the bi-weekly plan usually charge a "service fee" to do this.
Save yourself some money. If you have an extra $3000 around each year, just apply it directly to your principle. There's no magic going on here.
