An exoplanet (or extrasolar planet) is a planet orbiting another star (the "exo" prefix means "outside" in Greek). Up until now, planet-hunters has found mainly gas giant planets, which are easier to detect than telluric planets. However, due to the increasing sensitivity of the detection methods, one already begins to observe the first planets of sizes comparable to the Earth.
You may find Exoplanetology on several cool web services.
Google Custom Search Engine (CSE)
http://www.google.com/coop/cse?cx=005451225522983698504%3Awqgymzhs53u&hl=en
Exoplanetology Wiki: http://exoplanetology.wetpaint.com/
On Freebase:
http://www.freebase.com/view/user/metapsyche/exoplanetology
On Netvibes:
http://www.netvibes.com/Exoplanetology
On Twine:
http://www.twine.com/twine/exoplanetology
On SocialMedian:
http://www.socialmedian.com/network/exoplanetology
On Twitter: http://twitter.com/Exoplanetology
On RSSMixer
http://www.rssmixer.com/mixes/8621-exoplanetology
On Tangler (Forum)
http://www.tangler.com/forum/exoplanetology
Google Custom Search Engine (CSE)
http://www.google.com/coop/cse?cx=005451225522983698504%3Awqgymzhs53u&hl=en
Exoplanetology Wiki: http://exoplanetology.wetpaint.com/
On Freebase:
http://www.freebase.com/view/user/metapsyche/exoplanetology
On Netvibes:
http://www.netvibes.com/Exoplanetology
On Twine:
http://www.twine.com/twine/exoplanetology
On SocialMedian:
http://www.socialmedian.com/network/exoplanetology
On Twitter: http://twitter.com/Exoplanetology
On RSSMixer
http://www.rssmixer.com/mixes/8621-exoplanetology
On Tangler (Forum)
http://www.tangler.com/forum/exoplanetology