I submitted a new Podcast (you'll be hearing about it soon ;-)) to iTunes Monday of this week.
It was in the index the next day.
One of the 123 Podcast Launch students submitted their Podcast to iTunes and received an email indicating their acceptance in 1 hour and 58 minutes.
I submitted the same Podcast to Yahoo a few minutes after I submitted to iTunes (priorities ;-)).
It still isn't in the Yahoo index.
Yahoo, you can do better.