i am using whatsapp in my iphone 3gs, but i find out after i switch off the screen, the wifi is off as well, so i cant received messages from it. My friend told me hers is on even the screen is off, and she can receive message is it true that wifi will turn off when u turn off ur screen?? coz she hv 3g internet in hers, where i dont hv, do u think that make the difference? 
