John McCain has a statement on Ted Kennedy today:

"Our thoughts and prayers go out to Senator Kennedy and his family. We hope and pray his doctors will be able to effectively treat his condition and that he will experience a full recovery. I have described Ted Kennedy as the last lion in the Senate, and I have held that view because he remains the single most effective member of the Senate."

We'll put up the other candidates' statements as they come in.

UPDATE: Halperin has Obama's statement from CNN:

I would not be sitting here as a presidential candidate had it not been for some of the battles that Ted Kennedy has fought.

Here's Hillary's:

"Ted Kennedy's courage and resolve are unmatched, and they have made him one of the greatest legislators in Senate history. Our thoughts are with him and Vicki and we are praying for a quick and full recovery."