Unfortunately, no, but I'd love to know what others say. I've recently compared its results with an iPhone, and the comparison is close but not exact. The main difference is in sizing—where the real iPhone tends to fit a site in its viewport no matter how large, where Mobilizer doesn't seem to scale it down by default, but just shows the top left corner if the site is fixed width.
Ultimately, there's no fully reliable test except on the deice itself ... which is a real pain for web designers, as there are hundreds of different phones out there.
Some OSed like iOS and Android have developer kits you can download and which have simulators. The iPhone simulator is pretty good, but I haven't looked at the others.