Added url reference for update_user parser. Added get_group to IAM. Note: The excon response is not properly adding the Arn to the Users because both the group and user have an element named 'arn'. I'm not sure how to handle this.

lib/fog/aws/iam.rb

@@ -17,6 +17,7 @@ module Fog
       request :delete_user
       request :delete_user_policy
       request :get_user
+      request :get_group
       request :list_access_keys
       request :list_groups
       request :list_groups_for_user

lib/fog/aws/parsers/iam/get_group.rb

@@ -0,0 +1,35 @@
+module Fog
+  module Parsers
+    module AWS
+      module IAM
+
+        class GetGroup < Fog::Parsers::Base
+        # http://docs.amazonwebservices.com/IAM/latest/APIReference/index.html?API_GetGroup.html
+
+          def reset
+            @user = {}
+            @response = { 'Group' => {}, 'Users' => [] }
+          end
+
+          def end_element(name)
+            case name
+            when 'GroupName', 'GroupId', 'Arn'
+              @response['Group'][name] = @value
+            when 'UserId', 'UserName', 'Path', 'Arn'
+              @user[name] = @value
+            when 'member'
+              @response['Users'] << @user              
+              @user = {}
+            when 'IsTruncated'	
+              response[name] = (@value == 'true')
+            when 'Marker', 'RequestId'              
+              @response[name] = @value
+            end
+          end
+
+        end
+
+      end
+    end
+  end
+end

lib/fog/aws/parsers/iam/update_user.rb

@@ -4,7 +4,8 @@ module Fog
       module IAM
 
         class UpdateUser < Fog::Parsers::Base
-
+        # http://docs.amazonwebservices.com/IAM/latest/APIReference/index.html?API_UpdateUser.html
+        
           def reset
             @response = { 'User' => {} }
           end

lib/fog/aws/requests/iam/get_group.rb

@@ -0,0 +1,44 @@
+module Fog
+  module AWS
+    class IAM
+      class Real
+
+        require 'fog/aws/parsers/iam/get_group'
+
+        # Get Group
+        # 
+        # ==== Parameters        
+        # * 'GroupName'<~String>: Name of the Group
+        # * options<~Hash>:
+        #   * 'Marker'<~String>: Use this only when paginating results, and only in a subsequent request after you've received a response where the results are truncated. Set it to the value of the Marker element in the response you just received.
+        #   * 'MaxItems'<~String>: Use this only when paginating results to indicate the maximum number of User names you want in the response. If there are additional User names beyond the maximum you specify, the IsTruncated response element is true.
+        #
+        # ==== Returns
+        # * response<~Excon::Response>:
+        #   * body<~Hash>:
+        #     * 'Group'<~Hash> - Group
+        #       * 'Path'<~String>
+        #       * 'GroupName'<~String>
+        #       * 'Arn'<~String>
+        #     * 'Users'<~Hash>? - List of users belonging to the group.
+        #       * 'User'<~Hash> - User
+        #         * Arn<~String> -
+        #         * UserId<~String> -
+        #         * UserName<~String> -
+        #         * Path<~String> -
+        #
+        # ==== See Also
+        # http://docs.amazonwebservices.com/IAM/latest/APIReference/index.html?API_GetGroup.html
+        #
+        def get_group(group_name, options = {})
+          request({
+            'Action'    => 'GetGroup',
+            'GroupName' => group_name,
+            :parser     => Fog::Parsers::AWS::IAM::GetGroup.new
+          }.merge!(options))
+        end
+
+      end
+    end
+  end
+end