Hello Ms. Nguyen,
What do you mean by "plot"? Are you geocoding / address coding the locations to a base map?
Usually what I do (in Texas) is acquire the parcel data (shapefile format) from a given county appraisal district (this can be free or may cost a fee). Then using the address I identify the Property ID number and use that to locate the parcel using ArcView. The vector layers I usually use are the parcel map, streets, and aerial photos.
Also for a really quick and free way try mapquest directions and add another address (I think it allows up to 10 addresses); Google will also do this, but you may get significantly more flexibility out of Google Maps Pro. Also check out ArcViewer it may be useful. ArcView (not viewer) would easily do this, but it costs $1500.00.
For Open Source solutions start here: