Maximum ring volume for one contact, vibrate for others (SMS) I keep my phone on vibrate all the day because of my work. So I mostly get back on people when I have the time.

However, I must be informed immediately when some server goes down. For that I have ordered a service which sends me an SMS when it happens. 

How would I have the phone ringing with a maximum volume for just one contact, while at the same time have everyone else on vibrate?
There are SMS apps in the market that allow you to customize notifications by sender.     Handcent SMS is the one that I've used.