Sharepoint 2010 Date Column Validation with [Today] Date

with new SP 2010 Column validation . 1st thought that came to my mind is date field validation with respect to today's date. then quickly create a date column TestDate and  and add the validation formula as below .
=[ TestDate ]>=[TODAY]

Then it will give you a error.
after some hit and trial I found actual expression should be
=[ TestDate ]>=TODAY()


Yapee......