Is there an application, which switches the availability to offline, when connected to Mobile telephone network (GPRS,UMTS) and going online again after wlan connection is established?

I'm asking because voice and im services are not allowed by the phone card provider.

Thanks for any feedback.

http://talk.maemo.org/showthread.php?t=42646

Thanks, seems to be a good start for setting up sth. kind of a python widget.