Mindy,
Disney divides their seasons into 5 categories, which can help you determine crowd levels. They are Value, Regular, Summer, Peak, and Holiday.
For 2008, the first week of October is listed as Regular Season. You can find Disney's current suggestions here:
Great Times To Visit
Fall is a beautiful time to be in Disney. The weather is great, and many guests want to visit the really great Mickey's Not So Scary Halloween Party. Also many schools are year-round, and families can take advantage of that fall break to visit. Because of these things, it's true that crowds levels have increased in recent years. This used to be a value season, and now it's moved up to regular. In my experience, though, it is definitely not peak season! It will not be that crowded at all, and your wait times will still be far shorter than they would be at many other times.
Do not worry! You will still have a great vacation, I promise! :)