Two questions, which are linked.
Occasionally there is some coverage in the media about the continuing discovery of planets around other star systems in the Milky Way, through the work of the Kepler telescope, and other initiatives. Is there a place on the web I can go to, to check what the latest thinking on all of this work is? I'm thinking of an up to date receod of things like numbers of candidate habitable planets discovered, where they are, stuff like that.
Second question, is there any work being done to try to identify such planets around either Alpha Centauri A or B? Is there somewhere I can go to on the web to see what the current thinking and evidence is from any work on these stars and their surrounding planets, and whether any might be in the 'goldilocks' zone for these stars?
There are several websites that maintain catalogues of exoplanet discoveries, with the two most well known being the Extrasolar Planets Encyclopedia (www.exoplanet.eu) run by Jean Schneider at the Paris Observatory, and the Exoplanet Data explorer (www.exoplanets.org) run by NASA, both of which provide facilities for plotting some of the basic parameters of the planets. Both of those catalogues also have links to other pages about exoplanets, including things like discussion of potential habitable zone planets (though on that particular point be warned that there is no definitive agreement about the location of the habitable zone so you will likely find significant differences between different sources).
Alpha Centauri, as you can imagine being the nearest star system to our own Sun, has been extensively studied for many years to determine whether it has planets. Last year a roughly Earth-mass planet was reported around Alpha Cen. B orbiting at 0.04AU (about a tenth of the orbital distance of Mercury), however there is considerable controversy surrounding this discovery and it has yet to be confirmed. The existence of any planets larger than around Neptune has already been ruled out in the Alpha Centauri system, however finding, or ruling out, small, Earth-size, planets at Earth-like orbital distances is exceptionally difficult. The Wikipedia article on Alpha Centauri Bb actually does a very good job of summarising the current situation.