Checking connection on Desire

I have an HTC desire with an unlimited data plan. I use the mobile internet daily, mostly for IM applications since I like being reachable that way. The problem is, the phone doesn’t tell me if I get disconnected for some reason.

The only way of knowing if I’m still connected is using an application (web browser/facebook widget) to check if it works. Is there some kind of app that can check the connection periodically and either beep when connection is lost or indicate the connection status on the screen?