That is a copyrighted map that I did a few years ago, though it's been nicely updated by Marty and is generally accurate.
A better map for the poster's query is another one I did -- the "Heart of San Pedro," also available with permission on this site.
The new maps (as of August 2006 -- Ambergris Caye and San Pedro town) I just did are in the downloadable version of "San Pedro Cool 2006-2007" at
www.belizefirst.com or at
www.belizenews.com --Lan Sluder