I just did my 2002 LS430 2 days ago; I got a brand new transponder key and instructions for about $150, and then I paid $12.50 to have the key cut which you will need to do before programming.
Instructions:
- driver's door closed, key removed from ignition switch
- obtain 1 already programmed black key
- insert already programmed black key into ignition
- within 35 seconds of previous step switch ignition ON and OFF 5 times
- open and close driver's door 6 times
- remove black key from ignition
- within 10 seconds of previous step insert new key to be programmed into ignition switch
- after 1 minute immobilizer lamp (to left of steering wheel column) will extinguish
- remove key
- DONE
NOTE: a maximum of 5 black keys and 3 gray keys can be programmed.
If you guys need the instructions for programming the transponder (remote trunk and door lock) let me know.