Well, I decided to splash out and buy the app - £1.59!
It works well and has a web interface for sending messages direct to your iPhone. It also gives you an email address to send notifications to.
Sending from the web interface gives a nice clean message, rather than the cluttered email notifications.

Logging in gives access to other stuff that I won't at this stage pretend to understand however, I'm sure the facility could be incorporated into Actions to deliver nice clean iPhone messages.
Examples of the REST API (whatever that is):
RUBY#!/usr/bin/env ruby
SINGLE_TOKEN = "[color=red]token goes here[/color]"
require 'rubygems'
require 'mechanize'
VERSIONLIB = '0.1'
HOSTNAME = "https://www.appnotifications.com"
a = WWW::Mechanize.new { |agent|
agent.user_agent = "AppNotifications Ruby #{VERSIONLIB}"
}
# Send a notification
a.post("#{HOSTNAME}/account/notifications.xml",
{ :user_credentials => SINGLE_TOKEN,
'notification[message]' => ARGV.join(" ")}) do |request|
end
CURL# Send a notification
$ curl -d user_credentials=[color=red]credentials go here[/color] \
-d "notification[message]=my message" \
-d "notification[long_message]=<b>Some HTML for the full layout page notification</b>" \
-d "notification[title]=A notification title" \
-d "notification[long_message_preview]=the notif preview" \
-d "notification[message_level]=2" \
-d "notification[silent]=0" \
-d "notification[action_loc_key]=Approve me" \
-d "notification[run_command]=http://maps.google.com/maps?q=cupertino" \
https://www.appnotifications.com/account/notifications.xml
# Get your user credentials
$ curl -d 'user_session[email]=youremail@gmail.com' \
-d 'user_session[password]=YOURPASS' \
https://www.appnotifications.com/user_session.xml