i use gwscan to write zeroes to 1st and last million sectors. free on gateway site. boot 98se floppy for it.

simple way to do it? boot up slackware from the disc and type dd if=/dev/zero of=/dev/hdx bs=1k count=1

and bam, nothing left

If you really mean wipe then this is great:
http://staff.washington.edu/jdlarios/autoclave/

If you just want to be able to create a new partition table without overwriting the drive contents you can simply delete the partitions.

Ya, i'm talking about a total wipe so everythings' empty when i load up my slackware

It's still not clear what you're asking for.
Deleting the partitions from an fdisk program (as would be available during the Slackware install) will let you completely repartition the disk "as though" you were starting from scratch. I say "as though" since that leaves all the old data written to the disk still there and repartitioning just tells the computer to consider the disk as blank. As far as any new install is concerned, it is blank. This is really all that is needed for a reinstall.
If you really want to "wipe" a hard drive you are talking about overwriting the contents of the drive with zeros, random numbers, combinations of both or etc. This can be very time consuming for large hard drives and is usually more called for when selling an old computer or hard drive.
That said, I usually zero a hard disk before a big reinstall.
Good Luck.