Is the radio a Honda item? Try contacting your local Honda dealer first. Some dealers may want you to bring the car in with owners documents to verify that you actually own the car before offering you assistance - for a fee of course!
If the radio is an after market unit then contact a decent radio repair shop to release the code or the radio manufacturers local agent for a reset back to factory code for you. In the meantime try 0000 or 1111 or 1234 on the radio presets just in case.