It has been up there for a couple of weeks now, but Driver 4: Parallel Lines is on the Wii (and PSP) Australian release list for March, now while this is far from a concrete confirmation; there is a couple of things that make it seem very plausible.

But the real reason why this rumour has credit awaits inside.
Driver Parallel Lines was released on the PS2 and the Xbox. The Xbox has been left for dead because the sales were never doing as well as they could. However the main reason why this rumour has credit is because the franchise is now owned by Ubisoft.

Ubisoft have promised 14 games by March for the Wii, now 7 games are out now and with Far Cry: Vengeance, Blazing Angels and Prince of Persia on the way another port of the Driver game doesnt seem so far fetched.

As usual time will tell.