How to let my site visitors plot their location in a Google Map?

Hi! I want to embed a google map on my site and let my visitors plot their location on the map. Is there a plugin that can let me do this easily?

I tried creating a map in Google Maps and embedding it in my site but visitors would need to go to the Google site so they can plot points.

I want them to be able to plot the map points on the site itself (without going to google).

Thanks for all the help. ??