This, from Marc Ambinder at the Atlantic, is really quite remarkable — not just that they would be doing it, but that they would talk about it:

With less than six months to go before he would be sworn in as the nation’s 44th president, Sen. Barack Obama has directed his aides to begin planning for the transition.
“Barack is well aware of the complexity and the organizational challenge involved in the transition process and he has tasked s small group to begin thinking through the process,” a senior campaign adviser said. “Barack has made his expectations clear about what he wants from such a process, how he wants it to move forward, and the establishment and execution of his timeline is proceeding apace.”
Last month, the Post’s Chris Cillizza reported that campaign advisers were sounding out John Podesta, a former White House chief of staff to President Bill Clinton and currently the president of the Center for American Progress, for his advice.
An aide confirms that Podesta will probably be asked to head the transition team, which would take over from the campaign if Obama wins in November, and would be tasked with ensuring a smooth handover of power….
A campaign spokesperson confirmed that transition planning had begun but would provide no further details. An adviser said that the campaign wants to keep the process as low profile as possible in order to minimize distractions.
A public announcement is planned for the fall.