It will be the most rewarding class you probably ever will teach. As others have said, patience and respect are very important. Just like every child learns a bit differently, you will find an even greater learning curve with these types of classes. Be realistic with what your goals are and make them achievable for each individual child. For some kids, that may be just getting through an entire class without running out. Communication with the parents is also going to be verrry important. Alot of these children may have many "teachers" or aids, so keeping things consistent is important. Don't be afraid to ask questions. Lastly it's going to be important to stress safety and awareness of what is going around them more than you might normally have to in a regular class. In my experience with an Autistic child she LOVED the trampolines and would go darting off right through the boys team tumbling passes to get over there, not realizing how badly she could get hurt. This happened week after week and then we implented all holding on to a jump rope when traveling from spot to spot.
Goodluck and feel free to ask any more questions!!