Mine went through ok on 5-16-08

Mine was there midnight the day mine was scheduled to be in there. I think that you should contact them before the 21st eventhough they say not to. On the 21st it will be very busy and it might take them over a week to get back to you.

Where you getting the 5/16 date off of your account (Where's my stimulus program) or from the printed schedule?

The Where's My Stimulus page actually looks at your tax account and will only give information if your refund is actually scheduled to go out. To get to this page, use Where's my refund and follow the links.

did you happen to use turbo tax? i got my 2007 income tax refund direct deposited so i assumed my stimulus check would be done the same way..well may 2nd came and went and no money. i called the irs..apparently if you used turbo tax (or any similar tax application) and had they processing fees taken out of your refund you will be receiving an actual check instead of the direct deposit so it will take longer.

A lot of people have thought they were getting direct deposit but for whatever reason aren't, so are assuming they'll get it earlier than they really are. For example, if you had a tax prep place do your return and had your fees taken out of your refund, you aren’t eligible for direct deposit.

Check your bank statement from when the original refund came - if it says "US Treasury" you should be OK for direct deposit as long as that account is still open, and you didn’t split your refund into multiple accounts. Otherwise, you’ll get a paper check

Yes, it seems so.
Mine was Due on 5/2 and it wasn't in my Bank until, Friday 5/16!