datetime/date comparison

I have a timestamp field in a customers table, which is set to the current date/time when a new customer is registered. I want to run daily reports listing all customers who registered that day, but I can't simply query the db (MySQL) where timestamp = '2000-0-521'. Do I need to check for "where timestamp >= '2000-05-21 00:00:00' and timestamp <= '2000-05-21 23:59:59"? If so, how do I convert a date to a datetime type?

any help is appreciated. thanks.
-- tine

if the date column is called register_date:

select * from customers where to_days(register_date)=to_days(now());

assuming you are running this the same day. If the next day you'll have to change the second part of the conditional to: =(to_days(now())-1)