Query regarding dialogue box when running a macro

Hi All

I have got the following code which currently inserts a new blank line whenever the informaiton in column a changes.

sub AddBlankRows()
'
dim iRow as integer
range("a1").select
'
irow=1
'
do
'
if cells(irow+1, 1)<>cells(irow,1) then
    cells(irow+1,1).entirerow.insert shift:=xldown
    irow=irow+2
else
    irow=irow+1
end if
'
loop while not cells (irow,1).text=""
'
end sub

What i am trying to do is make the macro work so that the user can select at the time the macro runs what column to use. For example if I wanted to insert a blank line whenever the data in column h changes you would input column number 8 when you run the macro.

Any help gratefully received.

Thanks

Stephen