Well, ok, so, which filesystem are you using? Here's a how to for ext2 (and I would assume ext3 as well?):
undelete how to
And as strange as this would seem, you can use an existing Winbloze OS to recover ext2 data:
http://www.r-tt.com/RLinux.shtml
I don't know how well either of those work, so hopefully some else might have some better ideas.
Good Luck