Glenn Fleishman had an idea for using voice over IP on the road:
I’ve toyed with buying Vonage service, and bringing the box with me when I travel so I can make unlimited calls and receive incoming calls when in a hotel room or anywhere I can bridge to a wired to Wi-Fi connection.
However, since my wireless plan already gives me nationwide roaming, that will probably be redundant, since the presense of high-speed connections and major wireless carrier networks tend to coincide.