Lingo

Lingo offers a full complement of telco standard features, like call waiting, call forwarding and voicemail. Similar to Vonage, Lingo works with specific hardware designed for compatibility with the Lingo network. Currently, it's difficult to find Lingo compatible hardware in retail outlets, instead requiring you to wait for shipment from the company on service activation. Lingo is possibly the most comprehensive VoIP service for international calling, with unlimited calling to the U.S., Canada and most of Western Europe (as defined in their terms of service). In addition to the base phone number for $19.99 monthly, an International number in selected countries is available for $10 per month.