how to create permission base on record? :)

[stamilo]

hi ,
  i see the question how to create permission, but i have other question
  how create permission base on record?

  like this:
  user a create a record recorda;
  user b create a record recrodb;

   i want that:
        user a only can see, edit , delete that records  created by himself;
        user b only can see, edit , delete that records  created by himself;

     but some guy may see all the records that create by user a and user b;

   .....
   :)

  thx!