diff --git a/lib/simple_form/form_builder.rb b/lib/simple_form/form_builder.rb
index c479dc6d..f655cb84 100644
--- a/lib/simple_form/form_builder.rb
+++ b/lib/simple_form/form_builder.rb
@@ -2,6 +2,7 @@ require 'simple_form/label'
 require 'simple_form/input'
 require 'simple_form/hint'
 require 'simple_form/error'
+require 'simple_form/map_type'
 
 module SimpleForm
   class FormBuilder < ActionView::Helpers::FormBuilder
@@ -10,6 +11,20 @@ module SimpleForm
     include SimpleForm::Hint
     include SimpleForm::Error
 
+    extend SimpleForm::MapType
+
+    map_type :boolean,  :to => :check_box
+    map_type :text,     :to => :text_area
+    map_type :datetime, :to => :datetime_select, :options => true
+    map_type :date,     :to => :date_select, :options => true
+    map_type :time,     :to => :time_select, :options => true
+    map_type :password, :to => :password_field
+    map_type :hidden,   :to => :hidden_field
+    map_type :select,   :to => :collection_select, :options => true, :collection => true
+    map_type :radio,    :to => :collection_radio, :collection => true
+    map_type :numeric,  :to => :text_field
+    map_type :string,   :to => :text_field
+
     def input(attribute, options={})
       @attribute, @options = attribute, options
       @options.assert_valid_keys(:as, :label, :required, :hint, :options, :html,
diff --git a/lib/simple_form/input.rb b/lib/simple_form/input.rb
index b1b4acc4..30c98aa3 100644
--- a/lib/simple_form/input.rb
+++ b/lib/simple_form/input.rb
@@ -1,20 +1,5 @@
 module SimpleForm
   module Input
-    Mapping = Struct.new(:method, :collection, :options)
-
-    MAPPINGS = {
-      :boolean  => Mapping.new(:check_box, false, false),
-      :text     => Mapping.new(:text_area, false, false),
-      :datetime => Mapping.new(:datetime_select, false, true),
-      :date     => Mapping.new(:date_select, false, true),
-      :time     => Mapping.new(:time_select, false, true),
-      :password => Mapping.new(:password_field, false, false),
-      :hidden   => Mapping.new(:hidden_field, false, false),
-      :select   => Mapping.new(:collection_select, true, true),
-      :radio    => Mapping.new(:collection_radio, true, false),
-      :numeric  => Mapping.new(:text_field, false, false),
-      :string   => Mapping.new(:text_field, false, false)
-    }
 
     private
 
@@ -23,7 +8,7 @@ module SimpleForm
         html_options[:class] = default_css_classes(html_options[:class])
         @options[:options] ||= {}
 
-        mapping = MAPPINGS[@input_type]
+        mapping = self.class.mappings[@input_type]
         raise "Invalid input type #{@input_type.inspect}" unless mapping
 
         args = [ @attribute ]
@@ -62,11 +47,11 @@ module SimpleForm
 
       def collection_radio(attribute, collection, value_method, text_method, html_options={})
         collection.inject('') do |result, item|
-            value = item.send value_method
-            text  = item.send text_method
+          value = item.send value_method
+          text  = item.send text_method
 
-            result << radio_button(attribute, value, html_options) <<
-                      label("#{attribute}_#{value}", text, :class => "radio")
+          result << radio_button(attribute, value, html_options) <<
+                    label("#{attribute}_#{value}", text, :class => "radio")
         end
       end
 
diff --git a/lib/simple_form/map_type.rb b/lib/simple_form/map_type.rb
new file mode 100644
index 00000000..aa5cceda
--- /dev/null
+++ b/lib/simple_form/map_type.rb
@@ -0,0 +1,14 @@
+module SimpleForm
+  Mapping = Struct.new(:method, :collection, :options)
+
+  module MapType
+    def mappings
+      @mappings ||= {}
+    end
+
+    def map_type(type, options)
+      raise ArgumentError, "You need to give :to as option to map_type" unless options[:to]
+      mappings[type] = Mapping.new(options[:to], options[:collection] || false, options[:options] || false)
+    end
+  end
+end
\ No newline at end of file