Below worked for me just two days ago... you DO NOT NEED to take it to the dealer and you do NOT need to disconnect the battery, this can all be done with a couple clicks on your radio and call into a phone number.
This was posted previously on another post...
Procedure:
01. Turn the ignition ON (The radio displays LOC)
02. Hold down the Radio Presets 2 and 3 buttons for six seconds
03. The radio display changes from LOC to a three-digit number. Write this number down. Don’t take forever, fifteen seconds max before the next step.
04. Press the AM/FM button
05. The radio display changes to another three-digit number. Write this number to the right of the first one.
06. You now have a six-digit number, the first three digits are from STEP 03 and the last three digits are from STEP 05
07. Call 1 800 537 5140
08. Press 1 then #. You’ll hear Invalid Code, try again
09. Press 139010 then #. You will be asked to enter your four or six digit code followed by *
10. Enter the number from STEP 6 then *
11. Listen to the four-digit number and write it down. It will be repeated twice
12. Turn the ignition ON (The radio displays LOC)
13. Use the MN and HR buttons to enter the code from STEP 11
14. Press the AM/FM button. The radio display changes to SEC
Your radio is now un-locked and usable
Helper2008, August 2008