Before messaging anyone...since this will just likely be ignored by most....I suggest strongly checking out the existing tutorials first.
You can find them here:
http://www.bully-board.com/index.php?board=158.0You will need the following tools:
Notepad ++ (or an IDE of your choice...just avoid regular windows notepad)
A .img archive tool....I wrote a couple that are posted in the downloads section. I have one that is command/script based and much more powerful which is a complete redo of an existing tool. There is also a gui based one I released which is a bit dated but still built strictly for Bully.
Paint software of some kind (only if you plan to do texture modding)
and lots of patience.
You will find that if you are very serious about learning how to mod, people here will fall over themselves to help you out. I myself as I find time will also give hints and tips here but since I no longer mod actively, there are others here that are more suited to the task of helping out a new modder. DaBOSS is one that has really made a name for himself and SWEGTA and quite a few others as well.
I wish you the best of luck in your time modding and welcome you to the community.
Oh, and you also will need a lua compiler. I released one strictly for Bully which is in the downloads section and I do plan to release a newer gui based compiler at some point....whenever I get my current projects all finished.