It's disappointing that she's leaving, but it was also the right thing to do. Hillary Clinton, though I do not support her over Obama, is no monster. These types of attacks cannot and should not be tolerated, and she had to go. MSNBC has her statement:
“With deep regret, I am resigning from my role as an advisor the Obama campaign effective today,” Power said in a statement released by the campaign. “Last Monday, I made inexcusable remarks that are at marked variance from my oft-stated admiration for Senator Clinton and from the spirit, tenor, and purpose of the Obama campaign. And I extend my deepest apologies to Senator Clinton, Senator Obama, and the remarkable team I have worked with over these long 14 months.”
Hopefully, after some time in the cold and some penance, she can make her way back.