shred, wipe, etc

Greetings,

Thank you for your work!

Do you know of any open source utilities to wipe free space on a drive. 
  It appears shred, and poossibly wipe, will securely delete either 
files or partitions.  I would like to wipe free space, and the only 
program I have found is van Hauser's secure-delete package from THC-- 
sfill specifically.

Would you consider adding sfill to your pacakges?

Thank you,

Tad