First off, unless the beer is still actively fermenting when you rack, or you are adding fermentables to the secondary, it's not really a secondary fermentation. It's a "conditioning".
Second, you should really never, under any circumstances remove the beer from the yeast until it is finished fermenting because you can seriously slow or even halt fermentation prematurely.
Third, unless you can purge the secondary vessel with co2 you really do run the risk of oxidating the beer. I do believe that a short conditioning time can be good for a beer, but only if you purge that container with co2 first.
Lastly, as was mentioned, this topic has been discussed at length ad nauseam, and a search may be beneficial. But we also like to hatch these things out ad nauseam over and over again because, well, that's what we do here at AHA.