How do I add the rel="nofollow" to user posts
 

I've been reading several threads on here as to how to set up automated methods to add the rel="nofollow" to posts made by users, but is there any way to edit a users post and add this manually?

You could do it by creating a custom bbcode. Take a look at digitalpoint as an example:

http://forums.digitalpoint.com/misc....bcode#nofollow

Check out my hack 'vbAnonymizer' (look for it in my profile). It allows you to do this.