Came across a trick today to enable the use of the [Today] function in a calculated column. I have outlined the method here in case the source disappears.
It is possible to use “Today” in a function as a reference to today’s date
(despite what SharePoint tells you). There is a very simple work around that
doesn’t involve very much effort or complexity.
First, create a new column in your list with the Column Name of “Today”.
Click “OK”. (It doesn’t matter what type of column or data it is, this is
just a place holder).
Next, create a column with the data where you would like to use “Today” as a
reference to today’s date. The column type should be “Calculated”. In the
formula field, create your formula using “Today” as if it held the current
SharePoint will calculate the formula based on the assumption that you will
be using “Today” as a reference to the new column you just created.
Next, edit the new column named “Today” that you created in the first step.
On the very bottom of the page, click “Delete”, to delete the column. In
your formula, SharePoint will keep the reference to “Today” but it will
change from referencing your column, to a reference to the current date.
This can be used in any of the Date and Time functions, but I haven’t tested
it beyond that.
If you want to edit the formula containing “Today” SharePoint will not let
you, and will give you the same error about not using Today or Me in a
function. To get passed this problem you have to temporarily create another
The same functionality will also work with Me.
Source was Chris Johnson’s blog: http://blogs.msdn.com/b/cjohnson/archive/2006/03/16/552314.aspx