user_mailer.rb

class UserMailer < ActionMailer::Base
  def activation_mail(user)
    setup_email(user)
    @subject += "Welcome #{user.username}, Please activate your new account"
    @body[:url] = "http://YOURSITE/activate/#{user.activation_code}"
  end
  
  def activated(user)
    setup_email(user)
    @subject += "Welcome #{user.username}, Your account has been activated!"
    @body[:url] = "http://YOURSITE/"
  end
  protected
  
  def setup_email(user)
    @recipients = "#{user.email}"
    @from = "ADMINEMAIL"
    @subject = "[YOURSITE] "
    @sent_on = Time.now
    @body[:user] = user
  end  
end