Ascension - Tag editing tool for Halo Reach (similar to Assembly) Alteration - Tag editing tool for Halo 3 (similar to Assembly) Liberty - Campaign Game Save.
No one from 343 will un-ban you know matter how much you plead your case. They dont even read these forums anymore. All bans are permenant with no right of reply. Modding is in breach of your XBL T&Cs so your ban is actually from Microsoft and not 343i anyway. 
They ban the console ID ( i think its the MAc address) from XBL and ban your Gamertag as well. The only way you are ever going to be able to play Haloor any other game online again is to buy a new Xbox and setup a new account and dont mod. At least you will have the old console with which you can stuff around with your modded content on. You should have chosen a different text color, it comes out badly on the forum background. Anyways, it's your fault for modding. If anyone had any sense they would do modding on an offline account or an xbox not connected to the internet.
Or, better yet, DON'T mod at all. Most of the time in a game/console's Terms and Conditions, modding is bannable. It amazes me that people come to the forums asking for forgiveness. What makes them think a company like Bungie or 343i (and 343 doesn't even look at these forums) will care?
Jojo mayer drummer. You broke the rules, why do you think they will forgive you?