Create Calculated Columns Using [Me] or [Today]

As many may know, when creating custom list fields,  SharePoint does not allow you to use  [Me] or [Today] in a calculated field type. 

Here's a workaround, using [Me] as the example. However, you can also use these same steps for [Today] also. 

1. In your list, create a "single line of text" field titled Me
2. Now create a "calculated" field titled CalcMe with the following formula =[Me]
3. Now go back and delete the first text field you created titled Me

By doing this you trick SharePoint into using the Me field. Hope this helps :) 

Source: http://abstractspaces.wordpress.com/2008/05/19/use-today-and-me-in-calculated-column/