In my previous post I was already enthousiastic about my sitemap being pickup by Google within a couple of hours. I can now say that it gets better than that.
Much better, even.
I just noticed that it has been picked up again this morning sometime between 8 and 9 am. So it's my guess that the sitemap is downloaded by Google on a very frequent basis.
Or maybe it is because I submitted it twice. Anyhow, it is on the move.