I performed a map overlay in Google Earth then saved the overlay as a KMZ file. Then logged into my Google Maps account and uploaded that KMZ file so the map overlay would appear on Google Maps. The download speed for this map image overlay on my iphone was still much slower than I'd like it to be. Next I decided to forgo using GE and creating a KMZ file, and I just logged into Google Maps performed a map overlay there using a PNG of my map. Result is still a slow download time via my iphone. Any ideas for how to make this overlay so that it downloads quicker for me? More bandwdth-friendly?
The general workflow would be something like this: Try saving your AI vector as a dxf file. This can be converted with a tool like ogr2ogr to a gis format such as a shapefile (or another vector gis format).
You will then have to georeference that resulting shapefile (not sure what would be the best tool here - I'd look to qgis first). After that is done, you could use ogr2ogr again to export the georeferenced shapefile to a KML file which can be shown in google maps.
Actually since qgis uses ogr as a backend, you can probably import the dxf directly in qgis and also export to KML immediately from qgis. If you find a good plugin for reprojecting vector data, you're all set with using qgis for the conversion.