The setup experience is best via a traditional browser on a desktop or laptop PC. You can access all the core features via a smarphone at www.google.com/voice/m, but the mobile interface is shoehorned into a smaller screen. I found Google Voice very easy to navigate on a Windows laptop running the Google Chrome browser, but a real challenge using a Samsung Rant phone.
To get started, you'll need to enter one or more phones to your Google Voice account. As the screen below indicates, this is a snap. (Note: I added the black smudge to the left of "Send feedback" to obscure the account's real user name and phone number.)
The setup process does raise security concerns. What's to prevent you from adding any phone number you want? Well, once you've entered a number, Google Voice calls it. An automated voice prompts you to enter a two-digit verification code (e.g., 80).
I added three phone numbers, two mobile and one home. Despite a couple of verification hiccups, the process was easy. What went wrong? With two of the lines (one home, one mobile), I had to verify the numbers twice. After the first tries, Google Voice posted this message in my browser: "We could not verify your phone. Please try again." I may have hung up too early after entering the digits on the first try, but I'm not sure.
Call Routing Good, Transcripts Bad
Google Voice's flexibility is fantastic. You can route incoming calls from your Google number to one or more phones, or send them directly to voicemail. You also can record custom greetings for individuals or groups, such as family, friends, or co-workers. If you're a Gmail or Google Talk user, your contacts will automatically appear on your Google Voice site. Also, any updates made to your contacts in Google Voice (such as changing a phone number) will appear in your other Google services as well.