Someone is going to post a more coherent example, but I do this all the time. I usually use an input box so its a simple Cut & Paste affair - and people are familiar with text boxes from Youtube, etc.
Add this code (modify it for your site) to your single.php or child theme:
Code:
<p><strong>Share This Post:</strong> <input type="text" name="linking" style="width: 474px; margin-left: 2px; padding-left: 4px; background-color:#fff; border: 1px solid #c0c0c0;" readonly value="<?php echo the_permalink() ?>"></p>
That will put a text box on your page that your visitors can copy just like on Youtube.
Example page from a site I am currently rebuilding:
http://www.ytunc.com/2011/01/28/fuck-and-a-facial/