How to create a Custom Content type without Title?
You can use the Auto Nodetitles module.


  "auto_nodetitle" is a small and efficient module that allows hiding of
  the content title field in the form. To prevent empty content title
  fields one can configure it to generate the title by a given pattern.
  
  When the token module is installed it's possible to use various node
  data for the auto generated title - e.g. use the text of a CCK field
  (since 5.x).