Since string theory predicted the existence of extra dimensions many Cavendish type experiments with improved technology were done. Up to now no deviations of Newton's gravitational law were detected. Now there is a proposal to optically trap supercold strontium atoms a few microns apart and measure the gravitational attraction. It would provide an alternative way to detect extra dimensions without the use of torsion balances and accelerators.
There is also a nice article on the landscape in Science Magazine. It gives a balanced view of the anthropic principle and its use in string theory landscape.