diff --git a/README.rdoc b/README.rdoc
index c89b79681..25b1a42d5 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -382,19 +382,28 @@ Alternatively you can set the default selector to XPath:
 Capybara allows you to add custom selectors, which can be very useful if you
 find yourself using the same kinds of selectors very often:
 
-    Capybara::Selector.add(:id) { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
-    Capybara::Selector.add(:row) { |num| ".//tbody/tr[#{num}]" }
+    Capybara.add_selector(:id) do
+      xpath { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
+    end
+
+    Capybara.add_selector(:row) do
+      xpath { |num| ".//tbody/tr[#{num}]" }
+    end
 
-These must always return an XPath expression as a String, or an XPath expression
-generated through the XPath gem. You can now use these selectors like this:
+The block given to xpath must always return an XPath expression as a String, or
+an XPath expression generated through the XPath gem. You can now use these
+selectors like this:
 
     find(:id, 'post_123')
     find(:row, 3)
 
-You can specify an optional :for option which will automatically use the
-selector if it matches the argument to find using ===:
+You can specify an optional match option which will automatically use the
+selector if it matches the argument:
 
-    Capybara::Selector.add(:id, :for => Symbol) { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
+    Capybara.add_selector(:id) do
+      xpath { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
+      match { |value| value.is_a?(Symbol) }
+    end
 
 Now use it like this:
 
diff --git a/lib/capybara.rb b/lib/capybara.rb
index 54e1561ed..0fef58acb 100644
--- a/lib/capybara.rb
+++ b/lib/capybara.rb
@@ -64,6 +64,10 @@ def register_driver(name, &block)
       drivers[name] = block
     end
 
+    def add_selector(name, &block)
+      Capybara::Selector.add(name, &block)
+    end
+
     def drivers
       @drivers ||= {}
     end
diff --git a/lib/capybara/selector.rb b/lib/capybara/selector.rb
index 2d8a98c40..a3eb4306b 100644
--- a/lib/capybara/selector.rb
+++ b/lib/capybara/selector.rb
@@ -1,14 +1,14 @@
 module Capybara
   class Selector
-    attr_reader :name, :options, :block
+    attr_reader :name
 
     class << self
       def all
         @selectors ||= {}
       end
 
-      def add(name, options={}, &block)
-        all[name.to_sym] = Capybara::Selector.new(name.to_sym, options, &block)
+      def add(name, &block)
+        all[name.to_sym] = Capybara::Selector.new(name.to_sym, &block)
       end
 
       def remove(name)
@@ -31,22 +31,40 @@ def normalize(name_or_locator, locator=nil)
       end
     end
 
-    def initialize(name, options={}, &block)
+    def initialize(name, &block)
       @name = name
-      @options = options
-      @block = block
+      instance_eval(&block)
+    end
+
+    def xpath(&block)
+      @xpath = block if block
+      @xpath
+    end
+
+    def match(&block)
+      @match = block if block
+      @match
     end
 
     def call(locator)
-      @block.call(locator)
+      @xpath.call(locator)
     end
 
     def match?(locator)
-      @options[:for] and @options[:for] === locator
+      @match and @match.call(locator)
     end
   end
 end
 
-Capybara::Selector.add(:xpath) { |xpath| xpath }
-Capybara::Selector.add(:css) { |css| XPath.css(css) }
-Capybara::Selector.add(:id, :for => Symbol) { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
+Capybara.add_selector(:xpath) do
+  xpath { |xpath| xpath }
+end
+
+Capybara.add_selector(:css) do
+  xpath { |css| XPath.css(css) }
+end
+
+Capybara.add_selector(:id) do
+  xpath { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
+  match { |value| value.is_a?(Symbol) }
+end
diff --git a/lib/capybara/spec/session/find_spec.rb b/lib/capybara/spec/session/find_spec.rb
index 033f58a7a..d5b62fdb1 100644
--- a/lib/capybara/spec/session/find_spec.rb
+++ b/lib/capybara/spec/session/find_spec.rb
@@ -64,7 +64,9 @@
 
     context "with custom selector" do
       it "should use the custom selector" do
-        Capybara::Selector.add(:monkey) { |name| ".//*[@id='#{name}_monkey']" }
+        Capybara.add_selector(:monkey) do
+          xpath { |name| ".//*[@id='#{name}_monkey']" }
+        end
         @session.find(:monkey, 'john').text.should == 'Monkey John'
         @session.find(:monkey, 'paul').text.should == 'Monkey Paul'
       end
@@ -72,7 +74,10 @@
 
     context "with custom selector with :for option" do
       it "should use the selector when it matches the :for option" do
-        Capybara::Selector.add(:monkey, :for => Fixnum) { |num| ".//*[contains(@id, 'monkey')][#{num}]" }
+        Capybara.add_selector(:monkey) do
+          xpath { |num| ".//*[contains(@id, 'monkey')][#{num}]" }
+          match { |value| value.is_a?(Fixnum) }
+        end
         @session.find(:monkey, '2').text.should == 'Monkey Paul'
         @session.find(1).text.should == 'Monkey John'
         @session.find(2).text.should == 'Monkey Paul'
@@ -115,7 +120,7 @@
       it "should find the first element using the given locator" do
         @session.within(:xpath, "//div[@id='for_bar']") do
           @session.find('.//li').text.should =~ /With Simple HTML/
-        end        
+        end
       end
     end
   end