ruby script/plugin install https://hattenschwetter.com/svn/hattenschwetter/rails_plugins/model_formatter/trunk/

  class Widget < ActiveRecord::Base
    # Set an integer field as a symbol
    format_column :some_integer, :as => :integer

    # Specify the type as a class
    format_column :sales_tax, :as => Formatters::FormatCurrency
    format_column :sales_tax, :as => Formatters::FormatCurrency.new(:precision => 4)

    # Change the prefix of the generated methods and specify type as a symbol
    format_column :sales_tax, :prefix => 'fmt_', :as => :currency, :options => {:precision => 4}

    # Use specific procedures to convert the data +from+ and +to+ the target
    format_column :area, :from => Proc.new {|value, options| number_with_delimiter sprintf('%2d', value)},
                         :to => Proc.new {|str, options| str.gsub(/,/, '')}

    # Use a block to define the formatter methods
    format_column :sales_tax do
      def from(value, options = {})
        number_to_currency value
      end
      def to(str, options = {})
        str.gsub(/[\$,]/, '')
      end
    end

    ...
  end

The methods of this module are automatically included into ActiveRecord::Base as class methods, so that you can use them in your models.

There is currently no advanced documentation for this plugin.