Hi
I am a newbie in zenphoto and
I 'd like to use google map on my site.
I 'd like to know where could I find a tutorial to do this.

I haven't used that plugin, but I think you will need to get a Google Maps API key first. Once you have that, you will need to activate the google_maps plugin on the back-end. Your theme will also need to support it (the default Zenphoto themes already do, I believe). The API key will need to be input into the plugin's options on the back-end as well.