Caracol Archaeological Project - http://www.caracol.org/
Caracol is the largest Maya archaeological site in Belize, Central America. In AD 650, the urban area of Caracol had a radius of approximately 10 kilometers around the site’s epicenter. It covered an area much larger than present day Belize City (the largest metropolitan area in the country of Belize) and supported more than twice the modern city’s population.
http://www.caracol.org/

Weatern Belize Regional Cave Project(WBRCP) - http://www.indiana.edu/~belize/
The Western Belize Regional Cave Project is designed to introduce experienced participants to the fundamental approaches to the practice of speleoarchaeology and to provide training in a variety of archaeological techniques. Lectures will provide an overview of Maya civilization with a particular focus on ideology and cosmology relating to the use of caves by prehistoric Maya. Participants will work together as a team in the field, executing excavations and performing survey procedures.
http://www.indiana.edu/~belize/

Lamanai Outpost Lodge - http://www.lamanai.com/
Lamanai Outpost Lodge is situated on the banks of a 28 mile long spring fed lagoon amid the remnants of a major Maya city.
http://www.lamanai.com/

Archaeology of K'axob and Xibun - http://www.bu.edu/tricia/index.shtml
Boston University provides the home base for both the K'axob Project and the Xibun Archaeological Research Project (XARP).Field work has been conducted at two locales in Belize under permit from the Belizean government: the archaeological site of K'axob, which is located in northern Belize, and the Sibun River valley of central Belize.
http://www.bu.edu/tricia/index.shtml

Izamal - http://mayaruins.com/izamal.html
In Izamal, more than anywhere else in the Yucatan, the superimposition of Catholicism and Spanish culture on top of Mayan tradition is visible. Long before the Spanish arrived, Izamal had been a prosperous ancient city, occupied continuously from the late Pre-classic period onwards (from about 300 BC). Twelve large pyramids made the city one of the most impressive in Yucatan.
http://mayaruins.com/izamal.html