Send an email notification out when a new message is waiting on the site for you.

app/controllers/message_controller.rb

@@ -14,6 +14,7 @@ class MessageController < ApplicationController
    
       if @message.save
         flash[:notice] = 'Message sent'
+        Notifier::deliver_message_notification(@message)
         redirect_to :controller => 'message', :action => 'inbox', :display_name => @user.display_name
       end
     end

app/models/notifier.rb

@@ -37,4 +37,16 @@ class Notifier < ActionMailer::Base
     @body['trace_name'] = trace.name
     @body['error'] = error
   end
+  
+  def message_notification(message)
+    @from_user = User.find(message.from_user_id)
+    @to_user = User.find(message.to_user_id)
+    @recipients = @to_user.email
+    @from = 'abuse@openstreetmap.org'
+    @subject = "[OpenStreetMap] #{@from_user.display_name} sent you a new message"
+    @body['to_user'] = @to_user.display_name
+    @body['from_user'] = @from_user.display_name
+    @body['subject'] = message.title
+    @body['url'] = "http://#{SERVER_URL}/message/read/#{message.id}"
+  end
 end

app/views/notifier/message_notification.rhtml

@@ -0,0 +1,5 @@
+Hi <%= @to_user %>,
+
+<%= @from_user %> has sent you a message through OpenStreetMap with the subject "<%= @subject %>". You can read the message at:
+
+<%= @url %>