Is there a way to write a macro that would erase some data inside a cell?

I have a column that contain the following data:

8/08/2007 08:35:31 AM IST (GMT +05:30)
10/08/2007 08:40:10 AM IST (GMT +05:30)
10/08/2007 08:40:10 AM IST (GMT +05:30)
10/08/2007 08:40:10 AM IST (GMT +05:30)
15/11/2005 07:17:15 AM IST (GMT +05:30)
15/11/2005 07:17:15 AM IST (GMT +05:30)
15/11/2005 07:17:15 AM IST (GMT +05:30)

And I would like the above data become:

8/08/2007
10/08/2007
10/08/2007
10/08/2007
15/11/2005
15/11/2005
15/11/2005

Please help because I have to edit data 1 by 1 everyday, and I have to do that more than 500 times. >.<

Thank you for your assistance in advance

Clair