Sounds easy enough but how many areas have a large enough wifi area to make this useful? Though, as time goes by, this has much more merit as more cities adopt the wifi technology.

I'm not crazy about the proposed VOIP over Wi-Fi because from what I understand, this technology relies upon private individuals providing a public connection on their Wi-Fi network. VOIP takes considerable bandwidth, so if someone were to talk at the same time I'm downloading or uploading, one of us is going to be miffed. Yahoo already provides VOIP on their Messenger platform. I've not used it, but supposedly you can make phone calls to other individuals on the internet; no matter how you are connected.

Also, Wi-Fi only works out to about 300 feet (at most), thus the term Hot Spot. Both the laptop and router would need a much more robust transciever for this idea to work well.

Wi-Max would solve the problems you raise, as the standard technology contains an algorithim that transfers a user to another tower station if a tower becomes overloaded. You are correct; WiFi doesn't do this. Various cities and even countries such as Chile are in the process of building country wide WiMax networks. This would also eliminate the need for a "robust transciever" connected to the laptop, and would allow companies to develop "portable" receivers for Skype/GoogleTalk.

done, http://tools.netgear.com/skype/