Is it possible to run a script in the editor so it doesnt have to run it again the runtime????

If you're talking about making an editor script run without having to press Play, then you want to take a look at the following:

http://unity3d.com/support/documentation/ScriptReference/ExecuteInEditMode.html

Yes, pretty much the entire editor / inspector system is written in scripts like this. See here http://unity3d.com/support/documentation/Components/gui-ExtendingEditor.html for some examples.