People at WebmasterWorld have been reporting this morning that Yahoo has finally made the switch from Google's Search to Inktomi's Search. It looks like Yahoo switched back to Google soon after. Lets keep watching Yahoo! Search.
SEO Chat thread covering this can be found here.
update: 3PM (EST) - Looks like Inktomi results are back in Yahoo Search. They don't match Inktomi exactly but they are not Google either.
Check out Jeremy Zawodny's blog entry, the Yahoo! engineer, a few days back on this.
update: 4:30PM (EST) - Google Results Back. Getting a bit dizzy here.