Use the FIPS.EXE program, included with most Linux distributions,under MS-DOS.
GNU parted, a partition editor, is stable enough for non-guru, mere-mortal use with relative confidence. Source code for the latest version is at: ftp://ftp.gnu.org/pub/gnu/parted/. There's also a boot disk image for resizing root partitions and for running parted on non-Linux machines. The disk image may be easier for beginners. Building from source could
require some extra configuration.
Parted also has tutorial-style, plain-text documentation for Linux and FAT (MS-DOS) file systems.
Also, some commercial distributions come with their own partitioning software, like Partition Magic.