I need your help...

What is the correct formula if I need to convert the date to a text value in
a month format?
I have two columns the DATE column and then the MONTH column.
Date - particular date in a month with MM/DD/YYYY value
Month - Mid Month if the date will fall from 1-15 and the End Month if it is
16-31.

Example:
Date Month
09/01/2008 Mid Sep
09/02/2008 Mid Sep
09/15/2008 Mid Sep
09/16/2008 End Sep
09/29/2008 End Sep
09/30/2008 End Sep
10/01/2008 Mid Oct
10/02/2008 Mid Oct
10/14/2008 Mid Oct
10/15/2008 Mid Oct
10/16/2008 End Oct
10/17/2008 End Oct
10/22/2008 End Oct

Thank you!