I have a need for a mapping program or app similar to the Google user maps. I need to be able to put addresses in and have them marked on the map. It needs to be persistent, that is, not disappear when I shut it down. Writing data out to a file is a major plus. Ideally, the program will allow sharing and collaboration, and if it’s a web app (acceptable for the short run) it needs to have some kind of privacy or security.
Can anyone recommend something really cheap (under $50) or even free?