Basically a 504 is a document that gives a child modifications and accomodations in the classroom, with homework, etc. It is not enforceable by law like an IEP, but it is easier for the student to qualify for. My son qualified for a 504 soley on the basis of his diagnosis of adhd (because it was interfering with his learning process in school). We put that in place to bridge the time between testing to see if he qualified for an IEP.
It's a good place to start since the IEP process takes a few months, but it is not something that is as concrete and enforceable like an IEP. Administrators and teachers must follow what is in the IEP or be in violatin of the law - there is not check and balances for a 504.
There are some great web sites that give ideas about accoms and mods for behavior and lds. Just have her google 504 accomodations and modifications.
Sharon