Do you mean that your BlackBerry speaker is buzzing or the any other speaker in the room but around the BlackBerry is buzzing? If it is later then it is normal. However, if it is not the later then you may have some kind of issues with the Berry. B'coz I have never a cell phone speaker buzz on some near by SMS notification.
__________________ Regards|Raja BlackBerry FAQ Nokia 2100 > Nokia 6100 > Samsung t319 > Nokia 5300 > Blackberry 8320 > Blackberry 8900 > iPhone 3GS > iPhone 4