how to implement facebook like button in asp.net pages or master page

1) One way to add the like button on your site.go to this page,
http://developers.facebook.com/docs/reference/plugins/like-box
just enter your facebook details then press on the "Get Code" button, u will get the copy & paste code like below.

This is an example:

<iframe src="http://www.facebook.com/plugins/likebox.php?href=http%3A%2F%2Fwww.facebook.com%2Fplatform&amp;width=292&amp;colorscheme=light&amp;show_faces=true&amp;border_color&amp;stream=true&amp;header=true&amp;height=427" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:292px; height:427px;" allowTransparency="true"></iframe>

 2) Another way To implement facebook like button copy & paste the below code replace "MahindraHomestays" with "your facebook id"

  <iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwww.facebook.com%2FMahindraHomestays&amp;layout=button_count&amp;show_faces=false&amp;width=50&amp;action=like&amp;font&amp;colorscheme=light&amp;height=21"
            scrolling="no" frameborder="0" style="border: none; overflow: hidden; width: 80px;
            height: 21px;" allowtransparency="true"></iframe>