Boot Managers

Extended Operating System Loader (XOSL)
Archive of a project to create a graphical boot loader. Includes manual, FAQ and source code.
http://www2.arnes.si/~fkomar/xosl.org/

GAG - Graphical Boot Manager
An open source graphical boot manager which supports up to 9 operating systems. Screen shots, version history and download.
http://gag.sourceforge.net/

Gujin Boot/Linux/System Loader
For PCs, analyzes filesystems, supports Linux kernel and chainboot.
http://gujin.sourceforge.net/

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.
http://www.masterbooter.com/

MATTsoft Boot Manager: MBTMGR
Boots multiple OSs, including several on one FAT partition. Download, installation documents.
http://www.penguin.cz/~mhi/mbtmgr/

Multi-booting Solaris and Other Operating Systems
Describes installing Solaris on a PC with other OSs, and joint use of Solaris boot manager and other boot loaders.
http://multiboot.solaris-x86.org/

Netboot
Includes boot manager functionality and boots Linux, DOS and FreeBSD via a TCP/IP network using BOOTP and TFTP.
http://netboot.sourceforge.net/

OSL2000
A universal boot manager allowing selection from a number of operating systems. Includes support for booting from USB, CDROM and other devices.
http://www.osloader.com

SOLO: Shag/Os LOader
Boot loader for Shag/OS which also supports, Linux and other PC operating systems. Includes source.
http://www.csh.rit.edu/~shaggy/software.html#SOLO

SyMon
Boot manager with support of up to 36 primary partitions,
http://symon.ru/usr/eng/about.shtml

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.
http://syslinux.zytor.com/

zBoot Manager
An effective boot manager, which allows the easy install and use of multiple operating systems on a single hard drive. Directly install other OSs to extended partitions and logic drivers.
http://www.zbmsoft.com