The Related Links Blender plugin provides a easy way to cross link posts. Target posts or external links with thumbs and SEO friendly markup.
Can you link outside to other website? --YES! New feature in v04.
Is there an easier way to choose targets? --YES! New feature in v05. FIND A POST button for searching for relevant post to link to
Should I use this in my production website? --not yet, hopefully soon
What is a post ID? --Every post in WordPress has a unique ID. It's not always easy to find, so I have included it in the options pane on a posts editor page.