This is awesome. Just tried it and works flawlessly. Would be cool to have "Settings" for it in the Settings Extras section. To be able to tweak options such as strength and duration of the vibration and enable/disable it altogether.

BTW, I had an app on N95 8GB which actually did the opposite. It will vibrate constantly while dialling and then stop when someone picks up. It was actually pretty handy as it gave me a constant feedback telling me that it's still dialling and stops if call gets picked up or if it dials out.