dalziel

Provides the ability to have a bookmarklet on your browser that will let you add any page as a link on your blog. 
Replaces the functionality of the Add Link bookmarklet that was removed in WordPress 2.5. For more information 
on what a bookmarklet is and how to use them see <a href="http://www.bookmarklets.com/" rel="nofollow ugc">bookmarklets.com</a>

Link This Bookmarklet

Provides the ability to have a bookmarklet on your browser that will let you add any page as a link on your blog.

singpolyma

Detects hCards, Facebook links, and Wink.com search results and allows the user to add the detected people to their WordPress links system.

Friend Bookmarklet

Generates a bookmarklet that makes it easier to add friends to the WordPress links system.

Link This Bookmarklet vs Friend Bookmarklet