Useful

The app worked straight away.

There are a few shortcomings.
a. The link to details is failing. (extinfo.cgi path maybe wrong?)
b. The option to vibrate the phone (HTC Desire) does not work.
c. One wish: Add an alarm to go off.
d. Widget with only a green or red symbol and click on it to go to the app as it is now.

Tested it with a failing host with 8 monitored services. The NagMonDroid took a bit longer to detect the problem.