Found it when I want to login in my Chase account today.
It seems that no posts are related to this bonus so far, so I wonder if Chase just released the news...
Please go from chase.com and refresh some times, you will see the ad.
You may even see a $50 sign-up bonus ad. <-- Do not click on it.
I found if you cannot see the $250 bonus, cleaning your browser cookie or closing all browser windows then reopening it may help.
Updated 3/15, 2007
It seems that Chase already removed this ad.
But you can still go from the links in quick summary if you're interested.
Updated 3/21, 2007
The promotion was dead for a period already.
Strongly recommend those who already signed up this card DO NOT call the CSR any more.
Chase has the right to explain their fineprints and change their rebate rules.
Please sit and wait, and let time answer if we can get the $250 sign-up bonus.