Credit goes to Seven for posting this:
You'll need 2 jack stands, a jack, and a bottle of Toyota super long life, pre-mixed coolant to get this done (you can get coolant from Toyota cheaper than Lexus. Its the same exact stuff).
When the car is cold (you havent driven the car in 2+ hours), do the following;
Step 1: Jack the car up by the front crossbrace behind the oil pan, till the car is up high enough so that the radiator fill point is the highest thing up.
Step 2: Remove the radiator cap, and top off the radiator (they sell radiator fill funnels at autozone that have a stopper plug in them. They're nice to have). If you have the funnel attachment, remove the plug and fill it so that its 1/4 full.
Step 3: Squeeze the lower, and upper radiator hoses to get any air in those out of them. After you cant get any more bubbles out, re-top off the radiator / refill the funnel to 1/4 level.
Step 4: Start the car and let it run. Keep adding coolant as needed. Once the thermostat opens, it'll start to bubble a lot. This is part of the reason why I said leave the funnel only 1/4 full. As the coolant gets hot, it'll also expand, and start to fill the funnel. If you aren't using the funnel, I let it spill out over the radiator for about a minute / 2 minutes, then cap the system and turn the car off.
Step 5: When it starts to bubble a decent amount, shut the car off, and let it cool off (at this point, I pull the cap off the expansion tank that is just behind the radiator, and make sure its at the full mark). If you are doing it without a funnel, just make sure that the expansion tank is at the halfway mark.
Step 6 (funnel only): when the coolant is bubbling not too much anymore I put the plug in the funnel and remove it, and put the cap back on the radiator.
Step 7: Lower the car and drive it around and see how it is. Now that everything is bled and topped off, you might hear *some* air bubbling (not as bad as before), but now that you have the expansion tank filled, it should start pulling any extra coolant it needs from there. After about a week, when the car is cold, check the expansion tank's level, and fill it to the level mark again if needed.
Enjoy, and post back with any other questions. If you do have questions though, re-read this first before asking.