Google wrote that the service is FREE from Google except for Google Voice charges for international calls and what you get charged by your carrier.
Pick it up here:
UPDATE: I also managed to ferret out the desktop page:
Google Voice gives you one number for all your phones, voicemail as easy as email, and lots of cool calling features like voicemail transcripts, call screening and blocking, conference calling and more.
The Google Voice dialer is an application that allows you to use Google Voice on your phone.
- Send and receive SMS messages from your Google Voice number
- Save money with low priced international calls
- Check your messages quickly with voicemail transcription and playback
- Enjoy native address book integration
- Easily make conference calls as well block and screen selected calls