You know...we actually do this regularly on the blog I do for Nerve.com. At the end of each post, we list related blog posts that we've done up in the past.
While I've already been linking to past posts within the text of my recent posts for Freelancedom, this challange made me think that perhaps I should add related links to the bottom of each post, as I've been doing at Nerve. So what I did was add related links at the bottoms of my most popular posts...the ones still bringing in new traffic months later.
Going forward, of course, I'll probably use this tactic within each new blog post.