By the way, I have a question: Can I use directly Google map in my PC? I mean is it necessary to make a web, and the map is accessed by the browser or I can use http://maps.google.com, export to kml file and process it?
I was under the impression that any Google Map/Earth API is a way to represent your data on the map. I don't think Google has provided a way to extract map information and use it in a custom client. In fact, I think maps.google.com has protections against non-browsers accessing the data.
Yes, the Google Maps APIs can now be used in Desktop applications, provided that they adhere to the other restrictions of the Terms of Service. Note that in order for a desktop application to be deemed "publicly accessible", there must be a publicly accessible webpage from which it can be downloaded. See Section 9.1 of the Terms of Service for more information