SysLinux Home of SysLinux (floppy), PXELinux (network), ISOLinux (CD-ROM), ExtLinux (ext2/3) utilities to boot Linux kernel; MemDisk, tool to boot legacy OSs (e.g., DOS) from nontraditional media.
SOLO: Shag/Os LOader Boot loader for Shag/OS which also supports, Linux and other PC operating systems. Includes source.
OSL2000 A universal boot manager allowing selection from a number of operating systems. Includes support for booting from USB, CDROM and other devices.
Netboot Includes boot manager functionality and boots Linux, DOS and FreeBSD via a TCP/IP network using BOOTP and TFTP.
MATTsoft Boot Manager: MBTMGR Boots multiple OSs, including several on one FAT partition. Download, installation documents.
MasterBooter Boot manager which can be used to install and maintain operating systems on a PC. Supports many operating systems. Shareware and registered versions available.
Gujin Boot/Linux/System Loader For PCs, analyzes filesystems, supports Linux kernel and chainboot.
GAG - Graphical Boot Manager An open source graphical boot manager which supports up to 9 operating systems. Screen shots, version history and download.
OSNews: Exploring the Future of Computing Weblog style online magazine on operating systems and computing environments. Daily updates, reader forum with many comments.
Operating System Sucks-Rules-O-Meter The web-based operating system quality and approval metric.
Operating System Growing article, with links to many related topics. Wikipedia.
How Stuff Works: Operating Systems Unbiased enlightening tutorial with impartial description of how OSs work, and many related links.
Convergence International The non-Wintel user group, supporting Acorn, Amiga, Apple, ARM, Be, NCs, PowerPC, Psion, Unix and other alternative operating systems. Services include a non-Wintel news summary.