Quote from Preston Forbes:
This one has been around for years
www.killdisk.com
But if you want to really protect your data also encrypt it with
either PGP Office the commercial product or the free open source offering from TrueCrypt.org.
Thanks I have used KD before, no GUI but gets the job done. The good thing about open source is that they are less likely to have back door in them for Big Brother which I know many commercials ones do.