A compant named Converse recently demo-ed software for java based phones that allow these devices to connect with and communicate in Second Life:

As demonstrated at the 3GSM Conference in Barcelona:

Attendees using Comverse's phones could see and manipulate avatars who appeared in Comverse's virtual 3GSM booth inside Second Life. Using simple commands, they could direct the avatar to walk around the booth, identify other avatars, and send them greetings via SMS, MMS, or instant messaging. And in a twist typical of today's virtual environments, people logged in to Second Life over traditional PC connections could walk into the virtual Comverse booth and pick up virtual phones that connected them directly to fellow members logged in from their real phones at the real booth.

See:
http://www.technologyreview.com/Infotech/18195/