Ok this is what you do:
1. FTP over to your xbox and copy the file default.xbe from your halo folder (main is f:\games\halo\) to your desktop.
2. Make a backup of the default.xbe.
3. Download
HALO Trainer PAL/NTSC4. Download
IPSWin 2.0 open it, and in "File To Patch:" is where you load default.xbe.
In "ISP Patch To Use:" is where you load the patch file (Mine was NTSC.IPS)
then click Patch.
5. Now copy the default.xbe file from your desktop back to your xbox where you have ripped a backup copy of Halo to (main is f:\games\halo\) and copy over your old default.xbe file but make sure you have a backup of it first I made a folder called backup (main is f:\games\halo\backup) thats where I saved my backup.
6. Now start up Halo.
7. In the game push down both Left & Right thumble sticks to open the trainer menu screen.
Thats it your done I hope I did not miss anything in there. B)