Can someone still sniff the SSID if broadcasting is off ?

Even if you turn off broadcasting of SSID in the AP (which you should do), SSID is still sent in clear text when clients associate to an AP... When SSID broadcast is off, the sniffer would have to wait for a valid user to associate to the network in order to see the SSID.

In other words, not broadcasting the SSID would delay, rather than prevent a sniffer from obtaining it. Still, turning off broadcast pings on the Access Point makes it invisible to 802.11b analysis tools like NetStumbler.