Free Map Data

Already in SylvanMaps Format

World Map Data

Digital Chart of the World in MDB format from 
US National Imagery and Mapping Agency(NIMA)

USA Map Data

Street Data from the US Census Bureau Tiger 2000
In Microsoft Access (MDB) format
In SQL Server (MDF) format

ZIP Codes for the USA 

Plus State, County, Incorporated (towns) Boundaries.
Extraordinary Stuff! From the Census 2000 Data.

In Microsoft Access (MDB) format
In SQL Server (MDF) format