Sorry that happened to you. Did you ask AA to put you on another carrier?? I understand that there are some issues now with re-booking on AA, which I don't really understand, BUT I think that if they cancel the flight they are required to try to accommodate you on another airline. It has only happened to us once, thank goodness, but when we had a flight cancelled from Tampa on Delta, we knew what other flight arrangements were available on other airlines and suggested a route on US Air. We actually got to SXM a few minutes EARLIER than our original flight!

Regardless, it's always better to book with the airline directly.