www.appleinsider has done measurements and the white iphone4 is 0.2mm thicker than the the black and some cases will not fit...
http://forums.macrumors.com/showthread.php?t=1144602 http://www.macrumors.com/2011/04/28/white-iphone-4-slightly-thicker-than-black-iphone-4/
oh like facebook and all that?..sorry mate dont use those sites..always wondered what people meant by tweet...lol i thought "do i stand on a box and start singing like a sparrow??"