The Elegant Universe
Particle physics has more immediate worries on its hands. String theory is a lot like several of the (current) developments in particle physics (ie: supersymmatry). It's elegant, and solves a bevy of problems, yet there is no experimental proof for them -yet-.
The upgrades to the Tevatron at Fermilab, and the completion of the Large Hadron Collider at CERN in 2006 will provide energy scales large enough to create and observe superpartners. (And perhaps the Higgs boson, if you're familiar with the Standard Model). On the horizon after that are are the Very LHC, or a giant linear accelerator -- then, and only then, are we going to get even close to start solving mysteries like this empiracally.
Bear in mind though, that Maxwells equations (and even Newton's) equations went unsupported for years (even almost a century) before they were widely accepted. Most of modern particle physics is young by comparision, and the energy barriers are much greater, so its not surprising there is no evidence so far.