I've done a new release of DynDNS which waits a couple of seconds before sending IP address updates.
This is because the Motorola Droid connects to Wi-Fi and then falsely reports that it's connected to the mobile network and then switches to Wi-Fi. That meant that it would send an update for the false connection. If we wait a couple of seconds then the connection has settled down and it correctly reports that it's connected to Wi-Fi and gives the correct Wi-Fi IP address. This is mainly relevant if the "Update Wi-Fi address" setting is off.