Here is a photoshop drawing of my current room layout.
It's not perfectly to scale, but you get the gist of it. The green box is my router, which needs to be somewhat close to the phone jack marked by the red circle. Therefore the router, irc server and my desk with my PC need to be somewhere around the red circle. The blue circles represent outlets to plug shit into, i have 3 power strips to work with as well. I don't actually have a desk like the one i drew yet, its sitting in my garage waiting for me to put it together after I plan out where its going, but thats where my current desk is. I obviously cant block off the door or my closet door and the lizard cage needs to be near at least one of the windows so he can get some natural sunlight.
You can either chop up that picture in Paint or something like that OR you can use this PSD
All the pieces of furniture are their own layer, for easy movement and rotation.