Ben Smith has the goods on a letter to Obama from an esteemed roster of neocons--including Bill Kristol, John Podhoretz, Pete Wehner, Max Boot, Cliff May, Randy Scheunemann, and other familiar fellow travelers--urging him "to fully resource this effort [in Afghanistan and] do everything possible to minimize the risk of failure."
But this may not be support the White House actually wants. The effect here will mainly be to brand this war as the latest neocon adventure, driving away yet more of the liberal support that matters most to Obama. (And not in an emotional sense--Congressional Democrats control the purse strings, remember.) Far more useful for Obama right now would be a similar statement from a bipartisan group of trusted foreign policy mandarins--the likes of Lee Hamilton, Chuck Hagel, Brent Scowcroft, Gary Hart, and so on. The trouble is, I'm not sure you could those folks to agree on any clear position right now, much less to sign off on something close to what the neocons are saying.