The Sleuth Kit is a C++ library and collection of open source file system forensics tools that allow you to, among other things, view allocated and deleted data from NTFS, FAT, FFS, EXT2, Ext3, HFS+, and ISO9660 images.
FFS File System Driver for Windows 2000/XP/2003, allows you to get a read access to FreeBSD, NetBSD and OpenBSD FFS(UFS) partitions.
*nix version of TrdFolder - free GUI based browser of ZX Spectrum images (TRD, SCL, TAP). features: - screen dump viewing - basic files viewing - delete/undelete files - 'move' images - create new image wizard etc
Not even in alpha stage, anyone doing java and interested to join please do, loads of stuff to do.