While reading this article from the NYT that shows how to make cheap calls from overseas with a cellphone, I was thinking of an alternative: Do you know of a compact IP phone that comes with two Ethernet plugs (usually labeled "WAN/LAN") so I could just unplug the Ethernet cable from any PC in a webcafé, plug it into the phone's WAN plug, re-plug the PC into the phone's LAN plug, and have the phone connect to a VoIP provider?
Another option would be a portable SIP client application that can be installed on any PC, ie. without admin rights etc., and a dumb USB handset.
A third option would be a USB handset that supports SIP (so that I can use any VoIP, not just Skype).
Has someone done this before and could provide feedback?
Thank you for any hint.