Android: WIfi and 3G connectivity

Question

hi,

Is there any way, When Wi-Fi is available i should be able to disable my 3G and 2G both(all operator based data ).

I want this to do from my application because

1> If both Wi-fi and 3G are available then it results in interminnent connectivity. 2> I may be charged if GPRS or 3G data are used, based on packets transferred.

Any guidance

Thank you...