There are no public trainers available yet, but you can modify your files fairly easily to give you unlimited ammo and infinite health. If you just want to make game a little easier, go to your difficulty options, on the main menu. There you can change the enemy and friendy AI levels to suit your taste. My default setting on Normal difficulty, had the enemy AI at .60 (which makes the AI seem to have Aimbot, as well as ESP). I changed to .30 (or whatever you like) and made the game much more enjoyable.
As far as editing, you need to download a .pbo extractor (you can get one at any ofp or armed assault fan site). You need to decyrpt your mission or campain pbo. After that, put files in your username missions file, and edit missions to your liking. There is a script that you can copy paste, to give your vehicles/units, unlimited ammo, health.
I know this sounds complicated, but it is not. If you have worked with the mission editor, you can do this, it just takes about an hour to change all the missions.
Otherwise, you will have to wait until March 2, for 1.05 patch, and hope a trainer is made. I've tried to make one myself, but there are too many variables, so the the script is the easiest way for most people.