Dealing with Nulls, - use previous record

From: Kole (anonymous_at_discussions.microsoft.com)
Date: 06/22/04 

Date: Tue, 22 Jun 2004 12:09:08 -0700

Do u know of a function that will return a field from the
previous record if the current record's field is null? I
know this is available in Monarch, but do not know how to
do it in SQL Server.