When I'm doing one of my online research jaunts I usually start with a visit to Wikipedia. Below are links to what I feel are the main key topics surrounding Chronic Sinusitis. It's a great place to start!
The basics on the condition, and what distinguishes "chronic" from regular.
Gastroesophageal reflux disease. Like acid reflux but worse. Sinusitis-like symptoms are often caused by food allergies / GERD.
A reaction to certain types of yeast. It gets blamed for all kinds of health problems.
Small teapot-like thing used for rinsing sinuses. Lots of people swear by their neti as a cure for all kinds of things.
This is a newer procedure, presented as another option vs. FESS.
This is the "traditional" form of sinus surgery.