"Google Voice gives you one number for all your phones -- a phone number that is tied to you, not to a device or a location. Use Google Voice to simplify the way you use phones, make using voicemail as easy as email, customize your callers' experience, and more. Google Voice isn't a phone service, but it lets you manage all of your phones. Google Voice works with mobile phones, desk phones, work phones, and VoIP lines. There's nothing to download, upload, or install, and you don't have to make or take calls using a computer," explains the new help center.
Google Voice Blog mentions that the service added many new features: "voicemail transcription, SMS support, conference calling, GOOG-411 integration, low cost international calling". Voicemails are now searchable, you can embed them in a web page and you can receive email notifications. Text messages sent to your Google number are automatically forwarded to your mobile phone and they are also available in the web account, where you can reply to the incoming messages.
The following videos show how to use Google's new voice service:
To request a notification when Google Voice becomes publicly available, use this form. "We expect to have the service ready for new users in a matter of weeks, and are focused on opening it as soon as possible," promises Google.
{ Thanks, Nathan. Via Blogoscoped. }