I want a macro to merge a sheet of two column data to another sheet

Hi:

Please help me to write a macro for the following problem:
I have two sheets.
Sheet1:
Column A Column B
ABCuc24556 To be postponed
ABCuc24557 Discussion will be later
ABCuc40001 Not reproducble now


Sheet2:
Column A Column B
ABCuc24556 To be fixed in next release
ABCuc24557 Discussion will be later
ABCuc34567 New issue to be reproduced

After macro execution, Sheet2 should be merged in to Sheet1. Sheet1 will be as follows:
Column A Column B
ABCuc24556 To be fixed in next release
ABCuc24557 Discussion will be later
ABCuc40001 Not reproducble now
ABCuc34567 New issue to be reproduced


kasi