After paying off the mortgage the bank should go over your paperwork within a day or so and look and see if you have any money left in escrow.
If you do have money in escrow after paying off the mortgage then the bank should send you the money back within 30 to 90 days.
It's a good idea to contact your bank after paying off the mortgage as it sometimes speeds things up and you want to contact the county appraisers office as well and make sure the property taxes are going to be sent to you instead of the bank because if you don't get the property tax bill and don't pay it for 3 years then your home can be foreclosed on and sold at a tax foreclosure auction.
Also make sure the home owners insurance is in your name only as well since if something happens to the house and the banks name is still on the home owners insurance you'll have a much harder and longer time of getting the insurance to cover the damages to the home.