Excel 2007 : Macro for date related conditional formatting

Hi all....!

I have a spreadsheet that I use to dump large amounts of data in, many rows and many columns. The number of rows vary each time I use this spreadsheet. What I want to do is write a macro where a user can click on a button and 1- column b will be sorted in descending order (these are dates- sometimes there will be 5 or 6 rows with the same date) 2- use conditional formatting to highlight every other date group. Can someone help me? Thank you in advance!!!

I want this: (date and description are in seperate columns)
B C
1/1/05 Description
1/6/05 Description
1/1/05 Description
1/7/05 Description

To look like this:
1/1/05 Description
1/1/05 Description
1/6/05 Description
1/7/05 Description