Should look something like
"SELECT Name, objectCategory, whenCreated FROM 'LDAP://dc=fabrikam,dc=com
' WHERE " & _
"whenCreated>='" & dtmCreationDate & "'"
Article from The Scripting Guy explains
http://blogs.technet.com/b/heyscriptingguy/archive/2006/01/25/how-can-i-get-a-list-of-all-the-objects-that-have-been-added-to-active-directory-since-a-specified-date.aspx