Get the number of indexed pages

How can I get the number of indexed pages of a domain?
The number which returns for searching site:domain.com .

 

go to google .com
and write
site:your sitename

 

You can also use Google Webmaster Tool. The update is faster.

 

Yeah I know site:yoursitename, and webmaster tools.
But I wanted to program something in php which gets the data.
I would like to know how can it be done using the API.

 

http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=link:[THE_DOMAIN]&key=[YOUR_GOOGLE_KEY]

I use that in my websites

 

Thanx imperialDirectory.
I know only how to parse XML files. What kind of protocol is this output?

 

Nevermind, it's json.

 

Yup, its Json. I think you can get it in XML as well. You can try http://xml.googleapis.com
Not sure will that works or not. I implemented this a year ago.

 

Thanks man, you were a great help.

 

You can also use Google Webmaster Tool.