I am totally new to this. I have a KML file of zip code boundaries. I want to create image from this KML, so that can use to overlay google maps. Can someone please guide me here?
Google Maps natively supports KML layers, you simply need to create a new google maps kml layer. Here's an example.
As a side note, using Google Earth you can view your kml by simply dragging and dropping the file onto the globe.