There was an interview with Senator McCain during the Republican convention of 2000, in which Senator McCain seems to say that running in 2008 was not in the cards.

From http://www.pbs.org/newshour/bb/election/july-dec00/mccain_8-1.html#:

JIM LEHRER: Finally, for the record, you have not lost your desire to be President of the United States, have you?

SEN. JOHN McCAIN: Certainly it's been put in deep cold storage.

JIM LEHRER: But you haven't lost it?

SEN. JOHN McCAIN: Well, in 2004, I expect to be campaigning for the reelection of President George W. Bush, and by 2008, I think I might be ready to go down to the old soldiers home and await the cavalry charge there.

JIM LEHRER: But between now and then you are, in fact, as we're sitting here now in Philadelphia, you are a national figure. Do you intend to remain one over these next few years?

SEN. JOHN McCAIN: I intend - I have four more years in my term, in this term as a United States Senator -I intend to remain active, committed, dedicated to the principles that I hold dear and the policies which I think should be pursued for the benefit of the American people. But I think I can do that as a member of the United States Senate very effectively.

If he thought he would retire by 2008, then how does he expect to be President of the United States until 2013?