To pass in a null to some stored procs (with older Vb6/ADO code) you can do this:
1) The VB code puts 1/1/1900 in the date and the proc converts it to null.
2) the proc code is shown below.
...
set @NullDate = convert(smalldatetime, '1/1/1900')
if @aTestTime =@NullDate set @aTestTime = null
...
Then your insert/update statement in the proc uses @aTestTime normally and this will put a null in the date field.
For our other code that generates insert and update statements just use null as you would in query analyzer.
Good luck
Doug