What if we find a new Earth?

In a decade or so, we may be able to detect Earth-like planets using
spacecraft currently being developed. We may even be able to detect evidence
for life on such planets (detection of methane through spectroscopy) and
even chlorophyll (?).

What could the discovery of such a planet lead to? An interstellar mission
using solar-sails? Plans for colonization? Focussing of SETI on such
star-systems?