Requirements can be found under FDICIA (FDIC Improvement Act) and 12 CFR 363. One source of reference can be found
HERE which is the OCC Internal External audit handbook.
You may also want to visit a recent thread titled "Sarbanes Oxley" which includes discussion regarding mgmt's internal control attestations, which you will be reguired to do...
I have not seen or attended any training specifically regarding audit programs/requirements for large banks. I am from Texas and spoke with TBA about possibly separating their audit school by instituion size because of the varing audit requirements and programs.
Hope this helps