Identifying and deleting all but the first and last cells for certain date
 

I have pulled phone call data from my phone system and
imported it into spreadsheet. I have one column of data.
The content of each cell is date and time information (ie.
12/4/2003 14:43).

I want to automatically delete all but the first and last
cells for each date. This will tell me when the first and
last calls were made for each date.

Any thoughts?

Thanks.