For those looking to change the bulbs on a 2008 Highlander, it's also possible to do so by reaching in from the hood!
Thanks LifeTech, I figured I'd try the same on my 08.
Here's how I did it:
Locate both bulbs locations with a flash light and get familiar with the placement. The 2008 takes H11 (I just put in Osram Nightbreakers, they do look much better than stock!)
Cautions, warnings: Make sure the car is cool as you will be reaching deep into the car and you don't want to get burned. Wear gloves to keep the bulbs oil free. For the passenger side, pop the windshield washer tube out of the bracket to make access easier.
You will need a slotted screw driver to release the center tab of the harness. Just insert and gently push down on the harness and the harness will come loose. Twist the bulb slightly and it will pop out. Change the bulbs and snap the harnesses back on. You're done!