Mapping program for Linux?

Does anyone know if there is a mapping program for Linux? In my job, I need
to create a route everyday. Between Excel and Streets 2002, I am able to do
this. Does anyone know if there are any programs or projects that are similar
to "Streets" for Linux? I know that various websites will give a map of a
particular address, but they won't give you are route between 50 in one
neighborhood.
Just curious.
Mark