backup home to a second hard drive? File size limits

[mmiller3@iupui.edu (Michael A. Miller)]

I've been using a script to tar and gzip nightly backups of user
directories in /home to a second hard drive.  The other day one
of the users (actually it was me :) hit the size limit so that
the resulting tar'ed gzip'ed file exceeds the 2^31-1 byte file
size limit. 

Can anyone suggest a way to anticipate that and split the archive
to avoid the file size limit. 

Mike