Puzzling question on Matching up dates and accounting for double entries

Hi there,

I have two worksheets in one excel file. The First Worksheet is a complete worksheet, and the second is to update the first.

First Sheet:
01/01/2005 .....more data.....
02/01/2005
03/01/2005
04/01/2005
05/01/2005
06/01/2005
07/01/2005
08/01/2005
09/01/2005
10/01/2005
11/01/2005
12/01/2005
13/01/2005
14/01/2005
15/01/2005
16/01/2005
17/01/2005
18/01/2005
19/01/2005
20/01/2005
21/01/2005
22/01/2005
23/01/2005
24/01/2005
25/01/2005
26/01/2005
27/01/2005
28/01/2005
29/01/2005
30/01/2005
31/01/2005

Second Sheet:
07-Jan-05 .....more data.......
07-Jan-05
09-Jan-05
10-Jan-05
11-Jan-05
12-Jan-05
13-Jan-05
15-Jan-05
16-Jan-05
17-Jan-05
20-Jan-05
21-Jan-05
24-Jan-05
26-Jan-05
27-Jan-05

As you can see, there are some points which have two days. So i would like to add a row so creating a double entry for that date. The question is, how do i go about marrying them up, and how to check for double dates and how to insert rows?

I am at a complete lost now!

Any ANY help would be greatly appreciated !!!