scan wifi in the neighborhood

inSSider is a Netstumbler alternative.
Both of the applications use your Wireless Network adapter to scan all the Access Points in your neighborhood. When you experiencing latency on you wifi you use these tools to see what channels are used in the neighborhood. Try to find a channel that is not used or selectt one that is used by the access points far away(week signal)....

You can also use these applications to align antenna's.

Also Xirrus Wi-Fi Inspector  is such an application. (didnt test it)