[Always On Venture Summit] I met with Isaac Levanon, CEO of 3DVU, and he showed me the Navi2Go technology. It is a 3D navigation software available now in the UK for Windows Mobile devices. It will launch in the U.S in Q2 2008, and Navi2Go will be available for Symbian next year. The rendering is done on the client and it does not require hardware acceleration.
You can also use the desktop version available on the Navi2Go website to plan your route and save it to your mobile device. I am not sure if 3D graphics are useful in this case or if the rendering is fluid enough on any devices, but it might please navigation system enthusiasts.
If you live in the UK, check it out on your mobile browser at m.navi2go.com