Rehnquist to Follow O'Connor?

According to Kos, rumor has it that Chief Justice Rehnquist will announce his retirement tomorrow morning. What will Bush do with two nominees? Will he try to elevate Thomas of Scalia to Chief Justice?

I'm still scared by these SCOTUS vacancies, but I'm less anxious about Rehnquist's (presumed) retirement than I was about O'Connor's.