"I'm deeply saddened by this turn of events and my thoughts are with Governor Spitzer's family during this painful time," Clinton said.
As the Associated Press notes, she went on to say that she looks forward to working with Spitzer's replacement, David Paterson.
Spitzer is a Clinton supporter, and his resignation could cost her a superdelegate. Paterson supports Clinton as well, but he was already a superdelegate and cannot have two votes. The Democratic National Committee will likely offer Paterson's original superdelegate vote, which he received through his DNC membership, to someone else.
A quick side note: The Washington Post reports that Clinton aides blame Spitzer's driver's license program for her fade from frontrunner status. As you may remember, the former first lady stumbled when addressing the topic at an early debate.
The Post also writes that Spitzer's present situation brings up uncomfortable memories for the candidate.
"Now, his apparent involvement with a prostitution ring...has brought back unhelpful memories of her own husband's dalliances in office," writes Peter Baker. "There on cable television again were pictures of Bill Clinton hugging Monica Lewinsky. And the image of Spitzer's wife standing painfully by his side while he acknowledged unspecified wrongdoing could not help but remind some viewers, and voters, of Hillary Clinton's own stand-by-her-man moment."