ISPhone are the ones to turn to for complete communication solutions. They specialise in IP telephony, fixed lines, mobile, and data services, along with a range of other communication services that will get your business operating more effectively.
Google Voice is a phone service provided by the makers of Gmail. It is an extremely well priced and competitive phone service that has VoIP rates which are literally pennies. In fact, if you are in the USA then calls are completely free throughout North America. The service also offers a number of other perks, such as voice transcription, conference calls, SMS to email, voicemail and even voicemail message to email services.