I'd like to share what I plan for the next releases of WiFi Probe:
Release will most likely be in the second week of January 2012.
It will add the functionality to detect if an open network with captive page needs login credentials or just has a checkbox and a submit button to confirm some kind of terms of usage. An icon will reflect the network's status.
I will look into the option to choose a sound as a notification for a free network. Maybe it will be included in the release.
I'd like to add the option to automatically pass the "checkbox and submit button" pages.
Some time in the future I will add the option to automatically submit the login credentials on captive pages.