There's an appealingly straightforward article in the SF Chronicle today about the pros and cons of the various different methods out there of preserving open bottles of wine. My own preferred method, which is not worrying about it & simply seeing what the wine tastes like the next day—an approach somewhere between rigorous scientific inquiry and absolute laziness—is partly predicated on the fact that, as a wine editor, I've got so much wine around I don't know what to do with the stuff anyway. (I mean, I know to drink it, but you get the point.)
Though the Chronicle article's author, Janet Fletcher, didn't conduct any rigorous testing of her own, apparently*, she does pull in some useful scientific commentary from professors at UC Davis and Purdue, along with thoughts from various Master Sommeliers, Masters of Wine, Elder High Wizards of Grapeomancy and whatnot. She comes to the conclusion that, generally speaking, you're kind of out of luck regardless of which method you use, in that your wine is going to oxidize to some degree no matter what. On the other hand, with young reds, a little oxygen can be a good thing—which is why decanting them isn't a bad idea either.