Backing up Windows files onto Linux tape drive

Hi all,

I'm looking for a way to backup directories specified by the users on the Windows machines on the internal network onto the tape drive of my RedHat 7.3 box.  It's a Travan 20GB drive (10/20) and it's mount point is /dev/tape (I soft linked that to /dev/nht0 which, I was told by Dell, is "n" for no rewind and "ht0" for the standard link).

I've tried several methods using tar and zip but none are really working well.  I've seen it backup, but I don't know how to advance to the next track, etc., when I'm backing up or checking it to see if things DID get backed up.  I've used mt and tar before to get something working on an old Sun machine, but that was a few years ago so I'm a little rusty on all of this.  

All the Windows drives are mounted into a directory /mounts/xxxx where xxxx is the computer name.  Most users have everything stored in My Documents so that's pretty easy.  Once I get some scripts written and organized (so that I can figure out how many can fit on a tape because they're only 10/20 tapes) I'll crontab them all at nights on a schedule.

Any ideas?

Thanks!
Mark