The technology already exists to pretty much answer that. I believe I heard a figure last week that about 350 "hot jupiters" have been detected in orbit around local stars.
Sensitive instruments are used to precisely measure the position of a star in the sky. We are capable of detecting "wobbles" in star positions, at least in the case of middle-sized stars and relatively-large planets. So far we are still working on more-sensitive instruments which could detect planets of any size around very large stars, or smaller planets around stars of approximately our sun's size.
The term "hot Jupiters" refers to large planets (llarger or roughly the size of our Jupiter, the largest planet in our solar system, about ten times earth diameter) which would be massive enough to create a detectable wobble in the position of a star. The star would have to be small enough for the planet's mass to cause the "wobble", the planet would have to be large enough, and the distance between them would have to be relatively small: their gravitational attraction is proportional to the inverse of their distance.
In such cases, the distance is close enough that the gravity also affects the planet. Typically this produces a planet which is "hot"- in that the constant gravity distortion of the nearby star, would keep the planet from ever being habitable by life as we know it, and it would also be constantly buffeted by solar winds (all of the nuclear radiation and heat/light that the star produces). It would make a very unpleasant place to visit.
Partly due to the extreme heat, a lot of the materials would be in gaseous states, possibly the rest molten, and not much in the way of solid surfaces anyway.
What we still seek to do is detect "rocky" planets- smaller, usually somewhat farther away from the star, less affected by the star's nuclear furnace, and more likely to be able to support life. They are usually a lot less massive (in Earth's case we are about one-thousandth the mass of Jupiter) hence harder to detect: we would cause much less "wobble" of our own star, given the presence of several much-larger planets already, and are also farther away than a "hot Jupiter" would be.
Given that the above discoveries are only about 10 years old themselves, there is no reason to assume that we would not be able to detect "earthlike" planets routinely within about another 5 to ten years, and likely identify several hundred of them within my expected lifetime.