You shouldn't need a bank to collect interest. I could be wrong, but as I recall municipal bearer bonds should have interest coupons attached to them. All you do is clip the coupons and submit them to the trustee bank that's noted for payment when the time's right.
If you want to sell them, your broker might be able to handle it (and if your they can't, check out Merrill, Schwab, Edward Jones, etc.).