Theming drupals page/form with tpl.php
In drupal we can have different .tpl.php files for node type, Often times it'd be nice to make a different template for just one specific node.
For page view
node-[nid]-page.tpl.php
specific nid
node-[type]-page.tpl.php
specific node type
But displaying drupals own page or form through tpl.php is one of the great feature.
You need to register theme function and tpl.php file by implement hook_theme.
code sample may be like this
Implementation of hook_theme