In Linux circles Netboot appeared first. According to the docs Jamie Honan was the person who coded up the first version and specified the format of the tagged image files. This version used assembler code taken from packet drivers to interface to the hardware, only Western Digital (now SMC) NICs in the first instance. It also required a DOS environment to compile. Later on Gero Kuhlmann took over the development of Netboot and made tremendous improvements to it. Among other things he created a harness that would simulate just enough of a DOS environment so that unmodified packet driver binaries could be used in a boot ROM. This allows any NIC on the market that has a packet driver to be used immediately. He also migrated the development to a Linux (Unix) platform.
Etherboot was ported from FreeBSD by Markus Gutschke. He made it compile under Linux and added code to support tagged images in addition to NFS boot. Since tagged images are a more general mechanism and requires less boot rom code, this has become the preferred loading method. Markus has also coded most of the additional features between 2.0 and 3.0, such as additional bootp tags, ANSI screen escapes, etc. Many of the features common to Etherboot and Netboot, such as the tagged image format, the support programs such as mknbi, and support in the Linux kernel for diskless booting, are by Gero or Markus.
Ken Yap came to Etherboot a bit later. His original objective was to produce a 16 bit version that could be used to netboot ELKS and other OSes on older CPUs. As these things happen, he got enticed into improving the code, doing structural rearrangement, and merging contributions from others, and is now the primary maintainer of Etherboot.
In the early days, the Etherboot web page was hosted by the Sydney Linux Users Group web site. Quite coincidentally and unrelatedly, Jamie Honan is one of the founding members of SLUG, so the story has come a full circle here. Since April 2000, Etherboot has been hosted at Sourceforge. Sourceforge has provided superb facilities for hosting community Open Source development.