Map - listing points in Polygons

We need a map that will allow us to do the following three things easily, 1. Import polygons via KML files. Currently we have almost 300 asymmetrical polygons. We want to name each polygon on the map. 2. Add markers (points) using addresses on a spreadsheet. Currently we have around 5000 addresses. 3. Generate a list showing which addresses are in which polygon We need to be able to do the above ourselves, easily and anytime that: 1. polygons change shape, are added or deleted 2. points are added or deleted It seems that maybe PIP or “point in polygon” is calculated through ray casting. There seem to be a lot of algorithms for this on the web. Any code used or written needs to be documented. This map is for a nonprofit group. It needs to be able to be embedded on any public website. It looks like Bing will let nonprofits use all their maps for free. Also perhaps anyone can use a Google map API for free (but not the pro or business maps). We want a free map, later we would like to add street views etc.