First, it can be writtem Iguaçú, Iguassu or Iguazu. It covers Brazil and Argentina.
Here are some references:
http://en.wikipedia.org/wiki/Iguaz%C3%BA_National_Park
http://www.cataratasdoiguacu.com.br/fauna_en.asp

I'd like to know if someone here ever photographed there. What lenses are recommended and what are the best times of the day for each location in order to get the best kight and/or animals are easier to spot.

Thank you.