I found this one out all by myself - and it works.
To find out the minute a page or site enters the Google index add a unique string to the page - "skajdfgwhfg" for example.
Then setup a mail Google Mail alert for that string with the web and news option.
As soon as any page with that string appears in the index it sends you an email alerting you.
You only have to set up the email once and use the same string all the time, you get an email as soon as any of your sites is added.
