i take mine to the laundry matt and use the big front loaders. then you can dry at home in the dryer with tennis balls (but i never used the balls). you have to make sure to get the comforter completely dry. i have heard if you don't have a very well made comforter, this can wear it down quickly.
Well, I have a cheap one (it was DH's in high school) and it gets washed several times a year and it is still doing well. Just make sure it is dry otherwise it can mildew.