Insert a block into a node or template in Drupal 7

To print the block you can use below code,

$addblock = module_invoke('addthis','block_view','addthis_block');
print render($addblock['content']);

addthis = "module_name" = This is module name can be found in block configuration URL or the name of the module's folder

block_view = Type of view

addthis_block = "block_delta" = This can also be found in the block configuration URL

*Configuration URL = Open blocks page in Drupal 7 which is "admin/structure/blocks", and click on "configure".

How to display a popup box containing webform using simple dialog module of Drupal 7

To display a webform first you need to create a webform, 
We will create a simple webform to demontrate this example,
Go to "Add Content" and create a webform containing a name field and an email field.
After doing this create a simple block and add following code to it,
<a href="/my-webform" class="simple-dialog" name="webform-client-form-562" title="My Webform Title" rel="width:900;position:[center,60];">Link TItle</a>