I use Google Maps, combined with Google Forms, linked by Google Fusion.
We have just developed a couple of simple maps: one highlights schools taking part in a project across the UK, the other is live database of providers of wood and fallen trees for play.
The Play Tree Finder has a simple Google Form to fill in for suppliers, it then live updates a map, with contact information etc on for schools to browse.
It is easy to sort – the Google apps all just interact simply, and there are script libraries out there you can copy and paste in should you need it to be cleverer…