Ta Dah!
http://nodexl.codeplex.com/Install procedure is VERY simple. Just download and run it, then start it from the shortcut it installs.
I will be honest, this thing is overly powerful and it took me a good hour and change to figure out what buttons do what. But, I can suggest a few things that can at least get the basics up and running.
0) This is usable only for Office 2007+. It installs a new tab along with the View, Developer and Data tabs called "NodeXL".
1) There's a simple "sample" document that comes with the tool, accessable via the NodeXL tab. That gives you a basic thing to poke with, and figure out what does what.
2) You input the links via the "Edges" tab, with each link going in the Vertex columns. The system DOES tolerate duplicates gracefully IE linking A->B, and then B<-A later will not cause it to explode. This
might factor into some options with the link lines that can indicate directionality.
3) To label the actual star systems, you do that via the "Vertices" tab. That should populate naturally once you've input the edges and asked it to generate a map.
4) The website shows some REALLY impressive tricks this thing can do on the fly, and I know I haven't played with this in the slightest.