PXE is a method of booting a device, to sum it up. It differs from most other methods, however, because it's done completly over the network, using no physical storage medium on the computer (less RAM). I document everything one needs (hopefully) to setup a PXE enviroment here, as outlined.
Generic Instructions to start
General Network (PXE) Booting - Get started!
Fedora Core - Info on how to PXE boot Fedora Core 10, but should pertain to FC1 through FC99 (in theory).
Knoppix - Info on how to PXE boot Knoppix 3.7, the popular linux livecd (now a live...network ISO!)
Debian - PXE boot the debian installer! Where isn't this useful?!
Windows 2003 - Use a driver to load the OS install components to memory, and PXE boot later Windows install.
Itanium - Info on how to PXE boot Itanium computers
PXE FAQ - The general PXE FAQ. Should answer a lot of the small stuff.
NFS-Root Information - All needed information on what your Linux kernel needs to use an NFS root.
PXE Capable Hardware
PXE Capable Hardware - list of PXE capable hardware. This is by no means a complete list.
Misc PXE-Related Documents
Memtest86 - This provides general information on Memtest86.