From the NYT:
Google stepped up its attack on the telecommunications industry on Thursday with a free service called Google Voice… [The service] is intended to simplify the way people handle phone calls, voice mail and text messages…
Google Voice allows users to route all their calls through a single number that can ring their home, work and mobile phones simultaneously. It also gives users a single and easy-to-manage voice mail system for multiple phone lines. And it lets users make calls, routed via the Internet, free in the United States and for a small fee internationally…
There are also a slew of other features available such as call screening, blocking, voicemail transcripts, email or text notifications, conference calling and more. See the Google Voice Features page for more info, including video demos of each feature.
The service is initially only available to a select group of users but Google says the general public will be able to use it in the coming weeks. Definitely watch for news when it does become available. This is going to be huge.