replace missing with previous value

[CHUL LEE <chullee@students.wisc.edu>]

Dear list,
It is not an issue of S-Plus, but I know someone in this forum can 
help me.
I have data which have missing cases. I want to replace this missing 
with above value. For example,

Col1      Col2
Smith     3
          2.5
          4
Johnson   4
          4.5
          3
          2.5


In this case, I want to replace Row 2 & 3 in Col1 with Smith, but Row 
5,6,&7 with Johnson. Is there a easy way to do by Excel or with 
Statistics programs? This data has more than 80,000 rows.

Chul