If you make one of those pushpin placemark things on google earth, you can then save it as a type of file called a .kmz file. You can then upoload this to the net somewhere, and then post a link to your kmz file from wherever it's saved to.

A bit long winded but you can provide very precise and accurate information this way.

So for example, I've placemarked West Kennet Longbarrow, and saved the file to my desktop, then uploaded it to a freewebs site. Then I can just copy the link to here...

http://www.freewebs.com/thewholedamnworld/west%20kennet%20longbarrow.kmz

Hope this helps.