Question: I don't want to share my PAGE, but I want to share a message with a short URL link to something.

Answer: 
I guess you're talking about this, right?

> 
> <http://www.facebook.com/sharer.php?u=http%3A%2F%2Fwww.google.com%2F&t=Google>
> 
> 
> 

It will let you share "www.google.com" on Facebook using the title "Google". All encoded, obviously.
I think you are looking for the Facebook API stream.publish function:

<http://wiki.developers.facebook.com/index.php/Stream.publish>

or FB.Connect.streamPublish:

<http://developers.facebook.com/docs/?u=facebook.jslib.FB.Connect.streamPublish>