You're probably better off with AppleScript and something like Butler.
You'll also probably need to use System Events, which is where scripts often go to die.
Basically, you'll tell System Events to tell Safari to copy
then activate your text editor
tell System Events to tell our text editor to paste
then activate Safari
This will give you a basic idea of how to use System Events. System Events is not terribly intuitive -- I hate using it, but I don't think you've got an alternative.
Once you've got your script, save it in the Safari Scripts folder (you may have to create it), and then install Butler, which will let you assign a keystroke (say, command-control-C).
With that, all you'll have to do is select your text, hit a keystroke, and you're in business.
mt