Sometimes, links get broken. Most likely many of your blog posts contain links. It is almost inevitable that over time some of them will lead to a “404 Not Found” error page. Obviously you don’t want your readers to be annoyed by clicking a link that leads nowhere. You can check the links yourself but that might be quite a task if you have a lot of posts. You could use your webserver’s stats but that only works for local links.

Broken Link Checker is a plugin for WordPress that will check your posts (and pages), looking for broken links, and notifies you on the Dashboard if any problems are found. By default all old posts/links are re-checked every 72 hours, or you can set a different time period.

There are several buttons for each broken link – “Details” shows more info about why the link is considered “broken”, “Edit Post” does exactly what it says and “Discard” will remove the message about a broken link, but not the link itself (so it will show up again later unless you fix it). Use “Unlink” to actually remove the link from the post. If references to missing images are found, they will be listed along with the links, with “[image]” in place of link text.

Pricing: Free
Requirements: WordPress 2.0.2+
Source: http://wordpress.org/extend/plugins/broken-link-checker/