PeLib   An open-source C++ library to modify PE files.

Resources about the PE format

Here are some links to documents, articles and other resources about the PE file format. Some of these documents are on my own webspace, some are links to other websites.

Documents
The Portable Executable File Format from Top to Bottom (Randy Kath)
The PE file format (Bernd Luevelsmeyer)
Microsoft Portable Executable and Common Object File Format Specification
ECMA and ISO/IEC C# and Common Language Infrastructure Standards

Articles/Tutorials
Peering Inside the PE: A Tour of the Win32 Portable Executable File Format (Matt Pietrek)
Under the hood - July 1997 (Matt Pietrek)
An In-Depth Look into the Win32 Portable Executable File Format (Matt Pietrek)
What Goes On Inside Windows 2000: Solving the Mysteries of the Loader (Russ Osterlund)
PE File Structure
Portable Executable File Format
Iczelion's PE Tutorials