Google map improve

Is it posible to improve google map extension such as it could be possible when you post an add to put the pin on the map where you want ?

I dont understand the question.

The pin is placed on the map at the latitude and longitude coordinates for the address you enter.

if you want finer control of the placement, than use latitude and longitude coordinates rather than entering an address and having the google geocode lookup the latitude and longitude.

To be able to drag/move the pin with the mouse in the point on the map where you whant. I saw this on other websites.

you should post feature requests to the product suggestions page:
http://www.webassist.com/community/feedback/dashboard.php

it would help if you included a link that demonstrates this feature of Googels Map API.