gistfile1.rb

class ContactMethod < ActiveRecord::Base
  validates_presence_of :name

  def self.select_options
    descendants.map { |c|       c.to_s     }.sort
  end
end

class Phone < ContactMethod
end

class TextMsg < ContactMethod
end

[gakins@Somnambulist contact]$ rails c
Loading development environment (Rails 3.1.3)
ruby-1.9.2-p290 :001 > ContactMethod.select_options
 => [] 
ruby-1.9.2-p290 :002 > Phone.new
 => #<Phone id: nil, name: nil, type: 0, created_at: nil, updated_at: nil> 
ruby-1.9.2-p290 :003 > TextMsg.new
 => #<TextMsg id: nil, name: nil, type: 0, created_at: nil, updated_at: nil> 
ruby-1.9.2-p290 :004 > ContactMethod.select_options
 => ["Phone", "TextMsg"] 
ruby-1.9.2-p290 :005 >