Formula to compare 2 sets of data using the date?

Hi all,

I have 2 worksheets of what should be identical data and I want to check that the dates on both correspond.

Basically I have 3 columns of data thousands of rows long with information in cell A and B with the date in column C (I have 2 sets of this data but the date may have been edited in one at some point didn't get updated in the other)

I know columns A and B are identical as they never change, all the data in cells A & B correspond exactly (As in cell A1500 is the same as B1500)
The date in column C is the only one that may have been altered.

Is there a formula that I can use on a separate worksheet?
Maybe put the data from worksheet 1 in columns A,B & C and the data from worksheet 2 in columns D,E & F and use a pull-down formula in column G?
And how would I identify a discrepancy if there was one?

Also, there are multiple instances of the same date so would cells in column A and C maybe have to used to compare with cells in D and F rather than just using the date columns (C and F) for comparison?

I hope that's not too confusing!!

I have 2003 and 2007

Any help is very much appreciated.

Thanks