Popup on "publish" button, multi-user.

Hey!

I want to open my blog for user registration, where the goal is that they are generating content. One thing I cant figure out is this: Once a user have created a post, and hit the “publish” button, I want to give them a popup. Just a simple one, saying something like “here’s the URL of the post you created. Share it on your Facebook, Twitter etc.”

Is there a simple way to do this? Some fancy plugin I havent found?

Thank you.