The proper combination of hardware, software, and drivers will enable you to effectively sniff wireless networking traffic.The following tools may be helpful:

Netstumbler
Netstumbler is more of a network scanner than a network sniffing tool, but is useful for listing networks detectable from your location. Netstumbler is an active network scanner that sends out probes that are detectable by others. It can be downloaded for free from www.netstumbler.org.

Kismet
Kismet is an open-source, free, wireless network scanner and vulnerability detector, that keeps track of wireless clients and their network associations. Unlike other scanners, it is a completely passive network scanner, and can be downloaded from www.kismetwireless.net.

Wireshark
Wireshark has a number of dissectors for wireless management traffic; however, it does not track by Service Set Identifier (SSID), nor does it show signal

CommView for WiFi
CommView for WiFi is a commercial wireless network monitor and scanner that can export in tcpdump format, which Wireshark imports and reads easily. CommView for WiFi can be downloaded from www.tamos.com/products/commwifi/