GNU GRUB is a GRand Unified Bootloader.
Integrate directory disk images and a bootloader into a bootable image
gPXE is an open source network bootloader.
A shell script that helps you install the GRUB boot loader on your system
0xFFFF utility implements a free userspace handler for the NOLO bootloader and related utilities for the Nokia Internet Tablets.
Petitboot is a graphical bootloader for the PlayStation 3.
Ubuntu Bootloader Manager is a graphical user interface for configuring GRUB’s menu.lst.
KBoot project is a proof-of-concept implementation of a Linux boot loader based on kexec.