PhoneFusion this week launched a free, downloadable application that lets smartphone users centralize their voice mailboxes and see a visual list of their messages on their phone.

Fusion VoiceMail Plus is similar to the iPhone’s “visual voice mail” in that it lets users deal with their voice messages on-screen, picking and choosing which voice messages to listen and respond to. Users can even see the incoming phone number and caller ID name from all of their incoming messages – even if they aren’t in the phone’s local address book. That allows users to immediately call back or text-message callers, even as their messages are aggregated across multiple networks and voicemail boxes.

Web services that allow this kind of Web/voice integration are becoming popular, such as RingCentral and Google’s Grand Central. They offer an alternative to carrier unified communications services, with the biggest differentiator being that Web-based alternatives tend to aggregate across multiple wired and wireless voice networks.

After signing up at FusionVoiceMailPlus.com, subscribers receive an SMS message with a link to download the Fusion Voicemail Plus application. The user then changes their voicemail access number from any of their other voicemail to a single PhoneFusion One phone number. All voice mails then go directly into the Fusion Voicemail Plus box.

Fusion Voicemail Plus is now available on any cell phone network for Windows Mobile 5 and 6. Future releases are scheduled for BlackBerry, Palm, Symbian, and LINUX mobile. A J2ME version is also planned.