How does NetworkManager select which wireless network to connect to?
NetworkManager only attempts to automatically connect to networks you have previously told it to connect to. If it finds multiple wireless networks that you have connected to in the past, NetworkManager selects the network one you connected to. If NetworkManager isn’t connecting to the network you want, try to force it to connect to the network you wish to be connected, and NetworkManager will remember that setting next time. In version 0.6.6 and later there is a profile editor that can be used to add/remove networks.