Lingo is like Vonage only with better international service. I'm considering switching to it to add a French phone number to our household in order to cut even further into our big Portugal Telecom bill (which is of course already deprived of transatlantic calls thanks to Vonage), and it's likely a UK number is going to come handy too. I need to research how to switch or possibly combine both services. Informed comments welcome.

Update: you can hook up both ATAs to the same router. Hmm, maybe I'm going to add a second handset to my AT&T 5830 wireless phone... but reviews are mixed, this will need serious homework.