Google Earth Signing Plans
You can create a signing plan on Google Earth using the signs from this website.  Here are the steps:

1) Click one of the signs above to obtain a placemark template.  Open it in Google Earth.
2) Right click on the icon and open "properties".
3) Find the string that looks like this:  "http://www.VillageGIS.com/signs/warning/W11-1.png"
4) Change the string it to the new sign URL location.

You obtain sign URL's by left clicking on one of the sign images then left clicking tomake it larger, then right clicking on it to get its properties.  Just copy the needed portion of the string and paste it into your the template placemark.