Send mail to selected users
Use simplenews module 

Simplenews


  Simplenews publishes and sends newsletters to lists of subscribers.
  Both anonymous and authenticated users can opt-in to different mailing
  lists. HTML email can be sent by adding Mime Mail module.
  
  Simplenews 7.x-1.0 has finally been released which includes a number
  of other important bugfixes, especially in the upgrade path.
  
  Features Sending nodes as newsletters to subscribers Multiple
  newsletter categories with separate settings Per category and
  multi-signup Blocks and Pages Subscriber management including
  mass-subscription and export Optional E-mail confirmations for
  anonymous users Customizable newsletter templates Support for HTML
  (including text alternative) newsletter when used in combination with
  a supported mail system module Views and Rules integration Support for
  multi-language newsletters