Possible Duplicate:
Is there a Wikipedia API?
Is there any API or any particular way to load pages to my site. For example if am viewing www.mysite.com/php , its should display a block which contains data from wiki!
Please give a sample example too
Yes, the documentation for the Wikipedia API shows up very near the top of a Google search for Wikipedia API.
Wikipedia has an API, see:
http://en.wikipedia.org/w/api.php
You can use this for loading contents, though be careful not to simply 'data mine' from Wikipedia as this will score your sites negatively in search engines.