The best Web site about Corozal by far is www.corozal.com.
It's put together by students at Corozal Community College and Corozal Junior College. Lots of info and mostly of a non-commercial nature, and links to most other sites on Corozal.
Corozal Town is one of my favorite places in Belize. Not so touristy, cheaper than most other spots, safe, friendly, drier climate than most other parts of Belize, close to Mexico for cheap medical care and shopping. Corozal district has no real beaches -- well, a few places such as Smuggler's Den have little human-assisted, and you can swim in a number of places including around Sarteneja and in Four Mile Lagoon -- but the fishing is good and the prices are right.
Not a whole lot to do or see -- a few Maya sites (Cerros, Santa Rita), one little museum, the Shipstern preserve, lots of sugar cane.
Belize First Magazine http://www.turq.com/belizefirst/