Tourists in the Bolivian Jungle - not specifically herps, but does include a bit about caimans and anacondas. Very well written.
http://www.theage.com.au/articles/2004/10/22/1098316847476.html?oneclick=true
http://www.theage.com.au/articles/2004/10/22/1098316847476.html?oneclick=true