What technology are they using ?

Here are some android app stores...

http://www.androidzoom.com/
http://www.appbrain.com/
http://www.androlib.com/

These sites get contents like version, size, description, etc., from official android market place...

What technology they are using to achieve this... I am going to make such site using PHP... what i want to use ?

Probably the Google API, they have an API for pretty much all of their products (probably including the Anroid marketplace), for which you can pull data.

Thank you very much... i saw a android market api but i don't have any idea about API so i leave it...

i like to know weather Google API consume huge server resource ?

Thank you