NT Kernel Resources: Open Resources

Headers
Windows 2000 Kernel Structures	These are some undocumented Windows 2000 structures, can be usefull for kernel-mode developer sometimes. This is a result of WinDbg extensions reverse engineering (contributed by Dan Partelly).
Source code
Windows NT Rootkit Source	Link to the NT Rootkit project is given in the Links section. It is a very interesting project for NT internals researchers, because it's source code contains lots of undocumented information and I believe it could be very useful for different tasks (not only for Trojan development). Here is a last source code snapshot I had a chance to download.
Open Source TDI Firewall	This is simple classic TDI filter driver which works like personal application level firewall. It can deny incoming and outgoing TCP connections, UDP packets and packets sent via raw sockets and can log its activity. Complete source code is provided (as a VC++ project). Initially contributed by Alexander Goncharov, in the meantime this project is available for public at SourceForge.net.
QuickSYS VC++ project	The program is a wizard to create a NT kernel driver framework in C. It will create a Visual C++ workspace. You can compile and link your driver in IDE. If you have SoftICE, it can generate .nms file. Source code included. It is free. Hope this helps. Authored by Chunhua Liu.
For IDA
Win2k Kernel Structures IDC	There is subset of Windows 2000 kernel structures in form of IDC file (for IDA). Hope it will make your life easier (at least in reversing part).