Anyone looking for a diagram for a 2006 V6 Toyota Tacoma belt has quite a few options to choose from. I pulled the diagram below from justanswer.com, where a forum user had posted a similar question to yourself. The diagram also appears on toyota-4runner.org.
If this isn't what you are looking for, take a look over at fixya.com, a general site for mechanical or electrical problems, where there a couple of ongoing threads regarding belt diagrams for 2006 Toyotas.Fellow Toyota owners would seem a sensible source of information, so perhaps you could join one of their online communities, such as tacomaworld.com or toyotanation.com. Once you've joined, you can ask if any other Toyota Tacoma owners can help you out with a belt diagram.
Lastly, you could always give Toyota themselves a try. Their US helpline can be reached at 800-331-4331, or you can forward an email via their website.
For a similar blurtit question, go to I Need A Toyota Tundra 2005 Wiring Stero Diagram, Any Ideas Where I Might Find One?, or watch this film on how to install a serpentine belt on a Toyota Tacoma: