[thirdhaf]

Unless the planets happen to orbit very stable stars in the plane that sometimes puts them between earth and their star. With Kepler and some earth-bound telescopes you can discern the brightness dips from these and sometimes glean minimal spectroscopic information on the planet. Direct imaging is possible with interferometric methods and some more innovative approaches [1] but require funding.

[1] http://en.wikipedia.org/wiki/New_Worlds_Mission