RE: Down $20 Cirrus Logic (a major supplier of iPod/iPhone audio chips) gave a preview of it's earnings - they are expected to miss. Apple, being one (if not the) largest recipient of Cirrus products is likely to blame for their bad earnings.
Pretty much, when an Apple supplier reports a bad quarter, people gear up for Apple to have a bad quarter. Apple punching through support at 419 triggers stop-gap sales and it continues to fall.
Don't be surprised if it falls below 400 in the upcoming days.
Sadly, we are midway through April with no new product news and no reason to be overly excited for their quarterly report. Could be a long one!