http://news.bbc.co.uk/2/hi/science/nature/default.stm (http://news.bbc.co.uk/2/hi/science/nature/default.stm)
here
How many of these gas giants have they found by now? 200 odd is it?
At the moment planets are discovered through dimming of distant suns (their orbit occluding the sun). Larger planets (gas giants) create such a dimming, whereas the dimming caused by Earth-sized planets might not be noticible with our current technologies. The fact we are finding so many planets out there is a good sign there are many planets of many sizes.