Only achievements.....
Sorry dude......make this easy on yourself so you dont have to keep browsing the internet for things that dont give you squat.. i use www.ign.com.
type in the game, then hit cheats, it should from there give you all you need.
hope this helps!Sorry Bud!
No cheat codes for Fifa 08, I wish there were though :(.
But what you can do is edit your players so they are really good and it will help. If you are going for achievements and all, thats the only thing you can really do. Sorry man, like all EA games these days don't make cheats public or input them.