Do you pay taxes of anykind if you are a POD of a bank account

You have received some good pointers from the other attorneys. I find it unusual for the bank to require that you sign current W-9 forms as a result of being placed on an account under the POD designation. It sounds more like a joint account status. If you are a joint account holder, you could have responsibility for reporting income tax on interest (although in today's environment, it's insignificant). As a POD payee, you have no tax responsibility during your mother's lifetime. At death, it is possible (not probable from what you've said) that there could be estate tax liability at death. But that's only if your mother had a large estate otherwise (greater than $5.25 Million).
As pointed out by another attorney, clients are often confused with the designations on bank accounts. Joint accounts, POD Accounts, or other designations can be confusing. To be certain about the consequences you need more information.

You will not be responsible for any taxes as a "pay-on-death" beneficiary. However, you might want to double check that you are actually only listed as POD and not joint account holders. If your mother listed you as joint account holders then there are some risks and potential gift taxes involved. Some of my clients have had problems with Utah banks getting POD and joint account holders confused.

You should not be liable for any tax on the account until your mom passes away. After she dies you will begin paying tax on the interest. They probably had you fill out the W-9 as a precaution because you never know when someone will die.

You will have no beneficial or liability interest as a POD beneficiary until the person in question passes away. However, PODs are created by contract and I think it would be wise to review the contract to ensure that, under the terms of the contract, you have no other obligations.