HArddrive cleaning software

[Matt]

I need to wipe a HDD securely - anyone got any free software recommendations

[Charisma Bypass]

I use this
http://eraser.heidi.ie/

[Mr Sparkle]

i've heard good thinks about Boot and Nuke, plus the name is cool so you can't go wrong really

http://www.dban.org/

Edit: although might not be what you are looking for:

Darik's Boot and Nuke ("DBAN") is a self-contained boot disk that securely wipes the hard disks of most computers. DBAN will automatically and completely delete the contents of any hard disk that it can detect, which makes it an appropriate utility for bulk or emergency data destruction.