xls2kml is a VB script for excel that saves to KML
There is also an open office calc file if you prefer.
It offers tons lots of options and comes with cells pre-populated which you can clear to input your own custom icon urls and
generate a bare-bones KML file for google maps using the minimum Name, Latitude, Longitude & Icon url (from this or your site).
Here is an experiment with icon size adjustments and the results in google maps.