Well,
I cannot help you with the actual codes themselves, but I can tell you this:
If you are patient, you will find many sites for AR MAX codes if you just type in something like "Final Fantasy 12 Action Replay Max Codes" or something of the sort. Examples of US codes:
Infinite Gil
Infinite Health
Infinite MP
Have All Weapons
Have All Magicks/Technicks
Have All Skills
Have All Accessories
Have All Armor
Now, some examples of UK cheats would be:
Turn Vaan Into An Esper
All Summons
Infinite Health/MP
Maximum Cash After Buying/Selling Items
I hope that helped you somehow...