New to Mapserver

[David H. McCoy]

Hello!
 I'm new to Mapserver and trying to understand something. I'm working for 
company that has an application with a mapping component. Currently, that 
component uses Google maps. I am replacing the Google Maps API with 
Openlayers and the mapping component with Mapserver. The goal is that while 
a customer can elect to use say Google maps, they can also host the maps 
internally, thus having no external dependencies. 

In additional to server maps, does Map server actually have maps available? 
Perhaps a better question would be are there any open source or freeware 
apps comparable to Google maps that I can retrieve for local use and utilize in 
Mapserver?

Thanks for your time.