Hi guys,
If you need a basic mapping application, that's one thing.
If you need a stronger GIS appliaction, that's something else.

One strong, capable GIS application is ESRI ArcMap.
It's probably outside the budget of many very small firms,
but you can use it for site location analysis,
sales trade area building,
geodemographic demand estimation,
competitive analysis, etc.
It imports simple XY (lat - long) text files easily.

Best Wishes,
dvdtvshows of http://www.dvdtvshows.com