Not free, but Data Rescue II at ProSoft Engineering does an excellent job of recovery-- as long as you quit using the drive until they are recovered!
When you delete files, the OS now sees the space they used to occupy as open/free space to store the next file it wants to write so the more you use the drive, the less files can be recovered. You can download a demo at the link that give you an indication of its ability to recover files- and simple file deletions are usually easy to recover.