I want to put to rest the speculation and unfounded rumors of my imminent retirement. I am not about to announce my retirement. I will continue to perform my duties as Chief Justice as long as my health permits.
You can get the story and a little analysis from these links:
Chief Justice to Remain on Court (SC Nomination blog)
Analysis: Rehnquist stays, no two-seat strategy (SC Nomination blog)
Rehnquist silences retirement speculation (CNN)