In May WindowsPhone8 leaked that Windows Phone 7 Mango will support visual voice mail. Now with the beta in the hands of developers the option for activating visual voice mail has been found in the dialler settings of the software update.
The feature does not appear on all carriers, with AT&T only supporting it on on iPhones and Blackberries, but some people have been able to get it work on T-Mobile USA.
With the Mango release Windows Phone 7 is rapidly closing in a feature parity with other major operating systems, and with Tango and Apollo on the way will hopefully leapfrog them in 2012.
Thanks lennard for the tip.