GotVoice is available as a free service, with ads; Premium ($10/monthly), which offers more features; and Business (various plans, such as $50/monthly for five phones), which adds even more options. I tested the GotVoice Premium service for more than a month.
Unlike Apple's Visual Voicemail, GotVoice retrieves new voice-mail messages from multiple phones, such as your mobile, home, and office numbers. After signing up for the service, you give GotVoice the phone number and pass code for each voice mailbox that you want it to retrieve messages from. The GotVoice service "dials into" each voice mailbox, retrieves your new messages, records them as MP3 files, and forwards the MP3s as e-mail attachments to your chosen e-mail address. (The free GotVoice service doesn't forward voice mail messages as MP3 file attachments. You have to go to GotVoice.com to view and play your voice mail messages.) You can then choose which voice mails to listen to, like Apple's Visual Voicemail, instead of having to listen to each new message in sequence, as most voice-mail systems require.
You can also log into GotVoice.com and listen to your messages from within your Web browser, either on your computer on your Web-enabled smart phone. You can choose to have messages GotVoice retrieves left in your voice mailbox or automatically deleted.
The free GotVoice service automatically retrieves your messages three times a day, but the Premium and Business services automatically grab your messages every 30 minutes. Subscribers of AT&T, Verizon, and other cell-phone service providers can have unanswered calls forwarded to GotVoice, according to Bob Lloyd of the company's customer support services, thus eliminating the need to wait every 30 minutes for GotVoice to retrieve your messages. Each forwarded call will eat into your voice plan minutes, however. (I didn't test this feature.)