Display the day of the given date-ksh

Hi friends,
I need some urgent help on Dates in unix.
I have a date say - "20080706", i need some command to display the day, here its sunday(06). Please help me out.
FYI: I use Ksh.

I/P - 20080706
O/P - Sunday

If you have the GNU date installed:

date --date "20080706" +%A

Otherwise you can use the datecalc script of Perderabo:

http://www.unix.com/unix-dummies-questions-answers/4870-days-elapsed-between-2-dates.html\#post16559

Regards