User map plugin?

Is there a plugin that can allow site guests to enter where they live in the world, and add a pin on a world map where others can see? Essentially, I want to know where a vast majority of my site visitors live in the world so that I can plan trips to it for conventions and meet and greets. I don’t need or want any other information, just maybe their name and where they live. Is there something like that available? I know there are dozens of things similar to this, but I want the right one. I’d prefer that registration to the site not be required if possible, as this will only serve as a temporary thing.