First a warning- STAY AWAY from the website service called "radio-codes dot com." They have no security measures in place to know if the unit is stolen or not. So don't pay them and encourage such practices. besides, they're just going to do what you can do yourself for free, and in a more ethical manner for all.
Okay, that said, your code may in fact be found somewhere on the car. It will be five digits: Try for a small sticker in the glovebox or on the outer side of the glovebox. Maybe even try looking for it under the ashtray. Up under the trunk space somewhere. If it can't be found, the 8-digit radio serial number may be, and you will need that to get the code. However, you can get the serial number electronically on almost all models except '03-'07 Accords w/navigation in six, or six and 1/2 steps...
STEP ONE: get a pen and paper handy, or a friend with a photographic memory.
STEP TWO: turn on ignition
STEP THREE: turn on audio unit and check if you see "COdE" in display-- if not, pull the backup fuse or battery cables again for 1 minute or longer and until you do).
STEP FOUR: turn off audio unit.
STEP FIVE: press and hold the preset buttons "1" and "6" simulatneously, then turn on the audio unit. The display will toggle back and forth between two screens-- the first showing the letter U followed by four numbers (WRITE THESE DOWN!) and the second display showing a letter L followed by four numbers (yep, you guessed it WRITE THESE DOWN NEXT!)
Forget about the U and the L. The eight numbers -big or small in size- make up your serial number (NOT YOUR UNLOCK CODE).
STEP SIX: If the car is registered with Honda USA, you can simply go to the website
to get the radio unlock code for free. (they will tell you the info that you will need to prove you're not the theif who simply stole your radio (ie: the serial number you just retrieved, the VIN, and probably your name and the address the car would be registered with them under).
STEP SIX AND A HALF: If you don't have luck there, proof of ownership, the VIN, and the unit's serial number should be all you need to get it from a dealer. They might charge 25 bucks, or they might not if you seem like or act like a regular.
Hope this helps. My first solution. But it worked 100% for myself.