Derrick Tennant

This plugin adds attribution inputs to the media uploader and “edit media” page. It includes a number of creative common license, public domain, fair use, and standard copyright. It will link back to the author’s page at either the end of a post/page and/or the attachment page. If you have a Flickr API key, it can automatically pull information for Flickr images (copyright, author name, title, description, etc). 
It adds a few settings to the Media settings page. You can add a Flickr API key, or display Creative Common logos for their respective licenses.
To style the attributions, I’ve added these CSS classes:
<ul>
<li>a2k-container – A div that contains all of the other elements</li>
<li>a2k-sources – Contains the text “Source:” or “Sources:” depending on the context</li>
<li>a2k-title – The attachment title</li>
<li>a2k-copyright – The copyright information. It may or may not contain an img tag, depending on your settings</li>
<li>a2k-author – The author information. If an author link is provded, it will contain an a tag.</li>
</ul>
Feel free to contact me, emrikol@gmail.com, if you have any problems or questions.

Attributron 2000

Easily add attribution to attachments and have them displayed on your posts.

Coen Jacobs

Makes it easy to display a link to the Creative Commons license you desire in posts and pages.
It adds the following features:
<ul>
<li>Options to add a link to your Creative Commons license under all posts</li>
</ul>
Read more about this plugin on the <a href="http://coenjacobs.net/wordpress/plugins/creative-commons-suite" rel="nofollow ugc">Creative Commons Suite plugin</a> page.

Creative Commons Suite

Makes it easy to display a link to the Creative Commons license you desire in posts and pages.

Attributron 2000 vs Creative Commons Suite