I just wrote a widget that lets a blog admin pull a link category from any blog on the same WPMU installation. It is pretty much the bomb, and you are going to love using it so much that you may have to take downers in order to get yourself under control.
Side note: I’m going to start creating separate pages (as opposed to posts) for each of my software releases. That way all comments/support regarding a given plugin will be in the same place, with a pretty URL. That’s why I’m turning off comments on this post.