For $10 a month, users get unlimited local and nationwide calls (international calls will match what Google Voice charges), caller ID, call waiting, 911 service (kinda terrifying that I even have to mention that) and voicemail transcription. If you've already got a landline, you'll be free to keep your current number or choose a new one.
And, of course, you get a standalone, wireless handset with which to make your calls. Interestingly, since your Google Fiber Phone number "lives in the cloud," as the blog announcement states, you can forward all calls to your landline to your mobile device when you travel. Unfortunately, the service is only debuting in a few areas and will initially roll out exclusively to cities that already have Google Fiber installed. You can sign up for updates using this interest form.
Google isn't the only company trying to keep landlines around. Virtually every major satellite and cable provider, as well as the telecoms, offer similar phone services, though few are as inexpensive as the Fiber Phone.