How would I go about being able to do this? Couldn't see it being given as a regular link in the template :\
Assuming you mean posts and not comments, I'm not 100% sure but I believe http://wordpress.org/extend/plugins/noindex-archives/ is the plugin that your looking for. The description reads "This plugin can add rel="noindex,nofollow" to archive, tag, and category links. You can configure exactly which links are given which attributes. For instance, you could add rel="noindex,nofollow" to all of your tag links, rel="noindex" to all of your archive links, and nothing to your category links." So that would keep all of the posts that aren't on the main page having the nofollow relationship automatically.