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A planet with an estimated mass of 5.5 times that of the Earth has been found orbiting a red dwarf roughly 22,000 light years away in the direction of the galactic center. It orbits at a distance of 2.6 AU (about the distance from our sun to the asteroid belt) and is thought to have a 10 year orbit. It was discovered using gravitational microlensing.

http://skyandtelescope.com/news/article_1667_1.asp

They've only discovered this one planet orbiting that star, but there could possibly be more. So far, scientists haven't been able to find any planets that are Earth sized or smaller anywhere. That's not necessarily because there aren't any-- they are just hard to detect from Earth because of their size. Low mass planets don't reflect much light (or block much light when they transit in front of their star), and their orbits don't cause as much of a wobble on the stars they revolve around.

i remember hearing about that in a book i read. but i dont remember much. it said something talking about what will happen if some how both solar system collided with each other somthing like that.

I heard about something similar, where scientists found a planet about jupiter's size that orbits Alpha Centari. The planet is 3 million miles away from alpha centari[for comparison, mercury is 35 million miles away from the sun]. This gives it an approximate 3-day orbit. The planet is so close to the star, in fact, that it has an actual, physical[and visible] affect on the star. As in, the planet was found by watching alpha centari over the course of nine days, or some multiplicitive of 3. On the first day, the star would appear normal. Later that day, shifted to the right. The next day, it would appear to be going back to its original position that astronomers viewed it from. Later that day, it would begin moving to the left, and the next day, the star would appear dimmer. Notice, the dimming was caused by the planet moving in front of the star. And the dimming wasn't noticeable to anyone, really, as it was only dimmed by about 1.4% of its original magnitude. Only scientists with special spectrographic instruments could notice the dimming. This cycle is still continuing today - its all part of that planet rotating around Alpha Centari. And for those of you that don't know, alpha centari is the closest star to our star, currently. I believe it is alot like our star, too, in terms of composition, mass, size, brightness, and so on.

Actually, they've discovered twenty different multi-planet systems, and two-hundred five planets overall.
Heres the list.
None of those are around Alpha Centauri since we cant see any bodies as small as its likely to have orbiting it yet and no dust belt has been detected around the Alpha Centauri system so it may not have planets at all. That may be meaningless though, as Proxima may have ejected it on its arrival. It's not that big of a deal since the current estimates say that 12% of all stars have planets, so I'm sure we'll find something interesting out there. 3nodding

Wow! 3 years later and there is 332 of them now! biggrin

http://en.wikipedia.org/wiki/List_of_extrasolar_planets