The method used involves extracting the required details using OpenOffice.org, putting this into a MySQL DB and using PHP to extract the data in the required format for importing into Earth Plot which will put the pins into Google Earth.
One interesting problem was that Legacy stores location co-ordinates (latitude/longitude) in the format Degrees:Minutes:Seconds.xxx whereas Earth Plot requires them in decimal. A wide search on Google failed to provide a PHP script which made the calculation, so I ended up having to write one! The basic PHP, including this calculation, is given in the Map Using Google Earth tutorial on my FergysWebsite.
This tutorial describes how to use the method to plot the locations of the Fergusons born before 1902 who are entered into my One-Name DB. Looking towards the future, when I will have many more records - at present there are around 1500 - I would hope to have come up with a way of plotting their movements with respect to time. I suspect that this will not be too easy!