MiTeC's Windows Registry Recovery can read the files and even export them into REGEDIT4 format like a normal registry backup.
MiTeC Windows Registry File Viewer is
a viewer for Windows registry hives of
all (e.g. NTUSER.DAT, SYSTEM.1ST, SAM,
etc. - not .reg files). It displays
the file content in a tree view,
similar to the standard RegEdit
display and includes features like
registry searching, dumping and
exporting to REGEDIT4 format. The
program also allows you to explore the
NT/2k/XP security records. In order to
view most of the supported files, you
need to create a copy of them first,
as they cannot be used while they are
used by the NT/2000/XP system.

Windows Registry Recovery is freeware.