It seems there are still issues regarding worn cam lobes, broken rocker arms, etc. Some of those folks are out of warranty. It would seem a major help if there were some 'HOW TO'S'...like...
1. How to remove your rocker cover in the 2ZZ.
2. How to remove your valve springs in the 2ZZ.
3. How to remove your rocker arms in the 2ZZ.
4. How to remove your cams in the 2ZZ.
These all seem doable for the home mechanic with proper instructions.
I thought this integra example is one of the best I've ever come across:
How To: Install Valvesprings and Valve Seals - Team Integra
Also noticed this ...
I know I will be pulling my valve cover before the warranty is out and maybe earlier if there is any clacking noise noted from the valvetrain. For technical instruction on removing the valve cover as well as working on the entire engine, you can view a PDF of the official Toyota Celica Shop Manual here: NewCelica.org - Complete 2000+ Toyota Celica Resource
Once you are on the site, click on "Tech Info", then once the page opens click on "Manuals", and finally click on "Volume 2". The first section of Volume 2 contains the engine information and specifically the directions for removing and replacing the valve cover. Just make sure you are looking at the specific instructions for the 2ZZ engine. Both Celica engines are covered in this manual at the same time. Valve cover removal/replacement appears to be an easy procedure and it should also be very apparent if the 3rd cam lobe is worn with just a visual inspection.