The current Kepler telescope was designed to do just that, and has been finding planets for about 9 months now. The telescope will give us an order of magnitude more data about other solar systems, and is the first telescope that can find earth sized planets. As you can see from the posts on the article and here, the data will be very controversial up until the end of the mission and beyond. It will give us the best set of data on this for the next few decades.
The smallest I believe is 10x the earth’s mass. Not exactly ‘earthlike’.
Not all that much smaller than Uranus which is 15x. So a small Jovian gas giant.