Foreign Policy adds to the speculation:
Russian Prime Minister Vladimir Putin may be planning a return to the presidency, perhaps as early as 2009. That the whole story is reported second-hand and based on one anonymous source makes me a bit wary (Matt Drudge is less cautious). That said, the scenario doesn't seem completely outlandish and fits with some of the theories that were floating around back when Putin first announced Dmitry Medvedev as his replacement in December 2007.
Putin might also use the financial crisis to his advantage. Medvedev seems to be taking the lead in talking to the Russian public about the economy while Putin sticks to foreign policy, his strong suit. If the economic situation significantly worsens, Medvedev and his fellow "liberals" can take the blame for the fallout. Putin can then make his return to the presidency on a hardline nationalist platform. How much say Medvedev has in all of this is anyone's guess.
I would treat this story more as a calculated leak designed to test public opinion rather than a set plan of action, but it's certainly appearing more likely that the United States will be dealing with Vladimir Putin throughout the Obama administration, and perhaps into the next one as well.
Happily, such conjectures give us an opportunity to revisit Putin's rap career: